Hydrogen Water and Radiation Therapy: What Recent Research Suggests

What if the side effect radiation oncology patients dread most isn't the fatigue or the nausea — but a mouth so raw they can't eat, talk, or sleep through the night? Ask anyone who has sat through six weeks of head and neck radiotherapy, and oral mucositis comes up before almost anything else.

That symptom sits at an unlikely intersection of two research fields: radiation oncology, which has spent decades documenting how ionizing radiation damages healthy tissue on its way to a tumor, and molecular hydrogen research, a newer field studying whether the smallest molecule in existence can blunt some of that collateral damage. A 2026 randomized trial out of Taiwan tested the two together directly. Below is what that trial found, what a decade and a half of surrounding hydrogen-radiotherapy research says about why the connection might exist at all, and how two Lourdes Hydrofix owners — one a father managing a household of eight, one a wellness practitioner who evaluates tools professionally — describe fitting a daily hydrogen water habit into their own routines.

Molecular hydrogen itself is not a fringe research topic. More than 2,000 peer-reviewed studies have investigated it since Ohsawa and colleagues published the field's foundational paper in 2007, spanning more than 80 human clinical trials across conditions from metabolic syndrome to inflammatory disease. The radiotherapy research below is a smaller branch of that larger tree — but it's one of the oldest branches, dating back to the same general period the field itself began, and one of the few corners of hydrogen research tested directly in patients undergoing active cancer treatment.

What Radiation Therapy Does to Healthy Tissue Along the Way

Radiation therapy works by damaging DNA badly enough that cancer cells can't repair themselves and divide. That's the whole point of it, and it remains one of the most widely used tools in oncology, delivered either as the primary approach or alongside surgery and chemotherapy depending on the cancer involved. The problem is that ionizing radiation doesn't distinguish tumor tissue from the healthy tissue it passes through to get there — and the healthy tissue closest to the beam absorbs real damage too.

The Water Radiolysis Problem

Hirano and colleagues, reviewing molecular hydrogen's radioprotective potential in the International Journal of Molecular Sciences in 2021, described two distinct mechanisms of radiation damage: direct absorption of radiation energy into DNA, and indirect damage caused by free radicals generated when radiation splits water molecules inside cells — a process called water radiolysis. Since the human body is mostly water, that second pathway generates hydroxyl radicals throughout irradiated tissue, and the authors noted that low-dose radiation damage is driven mainly by these indirect, radical-mediated effects rather than direct DNA strikes.

Why Oral and GI Tissue Are Especially Exposed

Tissue that turns over quickly — the lining of the mouth, throat, and gut — is particularly vulnerable to this kind of radical damage, which is why oral mucositis, throat pain, and gastrointestinal symptoms show up so consistently in patients receiving radiation to the head, neck, abdomen, or pelvis. Rapidly dividing epithelial cells depend on their own DNA repair machinery working cleanly and quickly; hydroxyl radicals generated by water radiolysis interfere with exactly that process, on top of whatever direct radiation exposure the tissue absorbs.

None of this is a flaw in how radiation therapy is delivered. It's physics. Radiation oncologists already plan around it — shielding, fractionation schedules, and dose limits all exist because this collateral tissue damage is well understood and unavoidable at some level. The question researchers have been asking for over a decade is narrower and more practical: can anything reduce the radical burden on healthy tissue without protecting the tumor along with it? A therapy that shields the tumor as well as the healthy tissue around it would defeat the entire purpose of treatment — which is exactly why the selective mechanism described below matters so much to this specific research question.

Where Molecular Hydrogen Enters This Story

Molecular hydrogen is the smallest, lightest molecule that exists. It diffuses across cell membranes without needing a transporter protein, reaching compartments — mitochondria included — that larger antioxidant molecules can't easily enter.

A Selective Target, Not a Broad Antioxidant

Ohsawa and colleagues, publishing the field's foundational paper in Nature Medicine in 2007, reported something specific: hydrogen gas appeared to react preferentially with the hydroxyl radical — the same radical species water radiolysis generates during radiation exposure — while leaving reactive oxygen species that carry useful cell-signaling functions largely undisturbed. In a rat model of brain ischemia, hydrogen inhalation markedly reduced tissue injury consistent with that selective mechanism. Every hydrogen study published since, radiation research included, traces its logic back to this one paper.

That selectivity is the entire premise behind studying hydrogen alongside radiation therapy. A blanket antioxidant that scavenges everything indiscriminately risks interfering with the treatment itself — mopping up the very radicals radiation relies on to damage tumor DNA. A selective one, at least in theory, doesn't have to. It can, in principle, calm the collateral damage in healthy tissue while leaving the treatment's actual mechanism against the tumor alone.

This is also the reason molecular hydrogen shows up across such a wide range of oxidative-stress research beyond oncology — the same selective mechanism is the throughline connecting our coverage of hydrogen water and inflammation to the radiotherapy research here. Different tissue, different trigger for the oxidative burden, same proposed chemistry underneath.

The First Human Signal: Quality of Life During Liver Radiotherapy

Theory is one thing. A controlled human trial in actual radiation oncology patients is another — and this field has one going back over a decade.

Inside a 49-Patient Trial

Kang and colleagues ran a randomized, placebo-controlled study, published in Medical Gas Research in 2011, testing hydrogen-rich water in 49 patients receiving radiotherapy for malignant liver tumors. Participants drank hydrogen-rich water or placebo water daily for six weeks while undergoing treatment — nothing more elaborate layered on top of standard care. The researchers tracked global health status and quality of life using the Korean version of a validated cancer-specific questionnaire (the EORTC QLQ-C30, widely used across oncology research), alongside blood markers of oxidative stress and total antioxidant capacity measured before and after the six-week course.

Quality of life scores during radiotherapy were significantly better in the group drinking hydrogen-rich water compared to the placebo group, and blood tests showed reduced reactive oxygen metabolites alongside preserved antioxidant capacity in that same group — fatigue and general wellbeing, the two domains radiotherapy typically erodes fastest, moved in the hydrogen group's favor. Just as important for an oncology setting: there was no difference in tumor response to radiotherapy between the two groups. Nobody wants an antioxidant that happens to protect the tumor as well as the healthy tissue around it, and this trial specifically checked for that and didn't find it.

The researchers' own framing was measured — that daily hydrogen-rich water consumption reduced the biological reaction to radiation-induced oxidative stress without compromising anti-tumor treatment effects. Not a cancer treatment claim. A quality-of-life signal, tested directly in patients undergoing actual radiotherapy, with the anti-tumor effect of the radiation itself left untouched. Small trial, one tumor type, published over a decade ago — real limitations worth naming. But it's the trial every subsequent hydrogen-radiotherapy study, including the one below, built on.

A 2026 Trial: Gargling Away Radiation-Induced Mouth Sores

Fifteen years after that first liver-radiotherapy trial, a second research group tested a much more specific question, in the exact patient population where radiation damage to the mouth is most severe.

What the Head-and-Neck Cancer Trial Measured

Tsai and colleagues ran a randomized controlled pilot study, published in Integrative Cancer Therapies in 2026, testing whether gargling with hydrogen water could ease oral mucositis in head and neck cancer patients undergoing radiotherapy or combined chemo-radiotherapy. The researchers framed the work as part of a growing field they called traditional, complementary, and integrative medicine in oncology — approaches studied specifically for managing treatment symptoms, not for treating the cancer itself.

Patients were randomly assigned to gargle with hydrogen water or plain distilled water, and researchers assessed them at baseline and again on days one, three, seven, and fourteen using the World Health Organization's oral mucositis grading criteria, a validated pain inventory (the Brief Pain Inventory–Taiwan), an oral frailty checklist, and a head-and-neck-specific quality-of-life questionnaire (the EORTC QLQ-H&N35). Four separate outcome measures, tracked at five separate timepoints — a fairly rigorous assessment schedule for a pilot-scale trial.

Mucositis Scores, Pain, and Quality of Life by Day 14

The hydrogen water group showed significantly better oral mucositis scores by day seven, with the gap widening further by day fourteen. Pain scores dropped significantly in that same group by day fourteen, and quality-of-life scores improved as well. Oral frailty scores didn't differ meaningfully between groups — a result the researchers reported plainly rather than smoothing over, which is exactly the kind of honest, mixed reporting that makes the positive findings elsewhere in the same trial more credible, not less.

Their conclusion: hydrogen water gargling significantly eased oral mucositis severity and pain and improved quality of life in head and neck cancer patients undergoing radiotherapy, and may serve as a simple, well-tolerated complementary approach during cancer treatment. That's a pilot study, not a large confirmatory trial — the authors called it exploratory themselves — but it's a specific, recent, human result in exactly the patient population radiation oncology worries about most, gathered with a rinse-and-spit routine simple enough that a patient could realistically keep it up through a multi-week treatment course. Our broader look at hydrogen water and oral health covers the everyday side of that same tissue — plaque, gum inflammation, the ordinary wear on the mouth outside of a cancer-treatment setting — which is worth reading as a contrast to how differently oral tissue behaves under active radiation exposure.

Curtis's Case for Reading the Engineering First

Curtis, a father of six who has always taken a proactive approach to his family's daily habits, first heard about molecular hydrogen from a trusted friend who shared research articles and videos. "The concept made sense to me," he says — but what actually convinced him wasn't the research alone.

It was the engineering transparency. Curtis had looked at other machines on the market and noticed something missing. "Nobody else was really talking about the craftsmanship or the mechanism at which they produced hydrogen," he explains. "The fact that the company was even talking about that was important. That gave me confidence that Holy Hydrogen had a machine where they knew what they were doing." For a father managing a household of eight, that same transparency extended to practical output — one machine, kept full, replacing the idea of everyone in the family carrying individual bottles or tablets.

Curtis is candid in a way that reads as more credible than a polished testimonial, not less. He'll admit his own usage hasn't always been perfectly consistent week to week. But when he does use the machine, he says he can visibly tell the difference in the hydrogen bubbles it produces — "that's one of my favorite things about this," he says — a small, concrete detail that a company hiding something wouldn't bother pointing out.

What the Review Literature Says About Hydrogen as a Radioprotective Candidate

A single trial, or even two, doesn't settle a research question. What matters more is whether independent review teams, working from the full body of evidence, reach a consistent read.

Three Reviews, One Consistent Read

Hirano and colleagues' 2021 review in the International Journal of Molecular Sciences concluded that animal experiments and clinical trials have reported hydrogen exhibits a highly safe radioprotective effect, working not only as a selective antioxidant but also through anti-inflammatory, anti-apoptotic, and gene-regulation pathways inside irradiated cells. The review's own framing is worth sitting with: the authors describe hydrogen's prospects as a "novel and clinically applicable radioprotective agent" — prospects, not an established standard of care.

Hu and colleagues, reviewing the same question independently in Biomedicine & Pharmacotherapy in 2020, reached a similar conclusion — that hydrogen shows good potential in radioprotection, though the authors were careful to say the evidence warrants greater research effort, not that the question is closed. Zhou and colleagues, writing in the Journal of Cancer Research and Clinical Oncology in 2024, went further into mechanism: they reported that hydrogen appears to mitigate oxidative burden from radiation and chemotherapy while also showing immunomodulatory effects, including inhibiting T-cell exhaustion — a finding the authors framed as worth investigating further, not as an established clinical benefit. That same review also pointed out something easy to miss: the human gut produces hydrogen gas continuously via resident bacteria, a natural, everyday exposure the body already tolerates at scale — part of why the safety signal across this research base has stayed so clean.

Three independent teams, three different journals, three different years — and none of them concluded the question was settled. That consistency, not any single finding, is what makes the radioprotective research direction worth taking seriously rather than dismissing as a one-off result.

Radiation Doesn't Stop at the Mouth: The Gut Signal

Radiation to the abdomen or pelvis creates a parallel problem in the gut, and here the evidence is earlier-stage — animal research, not human trials yet. Xiao and colleagues, publishing in Experimental & Molecular Medicine in 2018, found that hydrogen-water administration increased survival and preserved body weight and intestinal lining integrity in mice exposed to total abdominal irradiation. Digging into mechanism, the researchers reported that hydrogen-water administration altered a specific microRNA, which in turn down-regulated a signaling protein called MyD88 in the small intestine after radiation exposure — and separately, that hydrogen-water treatment helped preserve the radiation-shifted gut bacterial community rather than letting it collapse further.

That's a mouse study, and it shouldn't be read as evidence about human GI side effects specifically. But it's a mechanistic thread worth naming, because it points at the same underlying idea as the mouth-gargling trial above: radiation damage tracks fast-turnover tissue wherever that tissue sits, and hydrogen's selective antioxidant profile is being tested against that damage at more than one site in the body. Mouth and gut, two different research teams, two different tissue types, one consistent hypothesis running underneath both. That same pattern shows up in slower-turnover tissue too: a 2022 case report describes a chronic radiation wound that finally closed under daily hydrogen therapy, months after conventional treatment had stalled.

Why Purity Is at Least as Important as Concentration Here

Concentration gets most of the attention in hydrogen water marketing generally. For someone already managing cancer treatment, purity deserves equal billing — arguably more, since a compromised immune system during radiotherapy or chemotherapy makes what else is in the water just as relevant as how much hydrogen is dissolved in it.

What JFRL Testing Adds to the Concentration Story

Separate-chamber electrolysis keeps the water chamber physically isolated from the electrode chamber, so byproducts generated at the electrodes never reach what ends up in the glass. Independent lab testing is what actually verifies that isolation is working — not a marketing claim, a measured result. It's a different question from the one our hydrogen water vs. alkaline water comparison walks through — pH and dissolved hydrogen gas aren't the same variable, and every trial discussed above tested the latter.

None of the trials above tested a specific brand or machine — they tested hydrogen-rich water as a category, produced by whatever equipment each research team used. That's worth being direct about. What separate-chamber electrolysis and third-party purity testing add is a way to actually verify that the water someone drinks at home resembles what a research protocol used, rather than trusting a PPM number printed on a box with no data behind it.

Lindsay's Practitioner Standard for New Wellness Tools

Lindsay, a wellness practitioner in Texas focused on nutrition and whole-body wellness, first heard about molecular hydrogen through wellness podcasts she listens to regularly. Her reaction wasn't skepticism — it was professional curiosity. "It's easy to implement," she reasoned. "We already drink water. So ultimately, you would just be drinking water that already had hydrogen put into it."

What separated a countertop machine from tablets or bottles, in her evaluation, was the engineering behind it. "This seemed like very thought-out technology," she explains, and she points specifically to separate-chamber electrolysis, Japanese manufacturing, and third-party testing as the reasons the machine earned her professional trust — not because a client asked her to try it, but because the specifications held up to the same scrutiny she applies to any tool she'd recommend. "I had heard from trusted sources, and other professionals in the field gave me confidence in this machine," she says.

As someone who evaluates wellness tools for a living, Lindsay is careful not to overstate her own experience. She describes health as "a journey, not a destination," and frames the Lourdes Hydrofix as one input among several she's watching over time rather than a single dramatic fix. That kind of measured language, from someone whose profession depends on getting these calls right, carries a different weight than an enthusiastic first impression.

A Simple Daily Habit, Not a Protocol

There's no standardized hydrogen water protocol for anyone managing radiation therapy, and nobody presenting one as though there were is describing real research. What the Kang and Tsai trials both tested was simply consistent daily intake over a fixed number of weeks — nothing layered, nothing elaborate. One trial had patients drink it; the other had patients gargle with it and spit it out. Neither asked participants to master anything complicated.

Fitting Hydrogen Water Around Treatment Days

Most owners anchor two full glasses to the morning, before food — the pattern covered in our guide to how much hydrogen water to drink per day. Curtis keeps the Lourdes Hydrofix's pitcher full and drinks straight from it rather than treating hydrogen water as a separate errand — "keeping it full and using it as our primary water source was easier than everyone in my family having bottles or using tablets," he says. Lindsay simply swapped it in for the plain water she was already drinking a gallon of daily during a fitness challenge. "It was easy to implement," she says. Fill it, run it, drink it — no new decision required either way.

Curtis and Lindsay Today

Curtis is candid that his own usage hasn't always been perfectly consistent, but he still believes in the machine and traces that confidence back to the engineering, not a dramatic before-and-after story. "When a company is that open about their technology, I think you've found something worthwhile," he says.

Lindsay, several weeks into her own routine at the time she shared her story, was just as direct when asked if she'd choose Holy Hydrogen again: "Absolutely." She's already thinking past the first few weeks. "We're really excited to see the longevity of using this product," she adds — the kind of forward-looking comment that only makes sense from someone planning to keep a habit going, not someone trying it once for a review.

Different professions, different reasons for looking into hydrogen in the first place — a busy father managing a household of eight and a wellness practitioner who vets tools for a living — but the same underlying standard: verify the engineering, then let a simple daily habit carry the rest.

Given These Criteria, Here Is the Machine Holy Hydrogen Carries

Given these engineering criteria, here's how the Lourdes Hydrofix Premium Edition addresses them. Its titanium and platinum electrodes are rated TP270C at 99.928% purity under an independent metallurgical certificate, No. 17-MANS-0078-B. It's designed to produce up to approximately 1.6 ppm dissolved hydrogen under normal conditions and approximately 120 mL/min of hydrogen gas depending on usage conditions, with independent testing by Masa International Corp. certifying output up to 134.2 mL/min under test conditions (Test No. MM03-6024-01). You can find the Lourdes Hydrofix in our hydrogen water machine collection.

The Certifications Behind the Machine

Japan Food Research Laboratories separately tested the water the machine produces and reported selected plasticizers, BPA, iron, and titanium not detected — Certificate No. 23028707001-0201, viewable on our certifications page. Every unit ships individually factory-tested with its own certificate of authenticity, backed by a full one-year warranty. Made in Japan — from a company that publishes every certificate rather than asking a reader to take a number on faith.

For anyone already coordinating care with an oncology team, the case here isn't that this machine treats anything — no hydrogen water product should ever be framed that way, and radiation therapy itself remains the treatment doing the work against the tumor. The case is narrower: the water behind a daily habit, especially during a demanding treatment course, should be as clean and well-verified as the habit itself.

Safety is the part of this research base that comes up least often and matters most. Hydrogen carries FDA GRAS (Generally Recognized As Safe) status, and across more than 80 published human clinical trials — including the two radiotherapy trials discussed above — no significant adverse effects have been reported at the concentrations studied. That safety profile is a big reason researchers keep returning to hydrogen as a candidate worth testing in already-vulnerable patient populations, where the tolerance for a risky intervention is understandably low. Still, always loop in an oncology team before adding anything — hydrogen water included — to a routine built around active cancer treatment.

Common Questions About Hydrogen Water and Radiation Therapy

Does hydrogen water reduce oral mucositis from radiation therapy?

A 2026 randomized pilot trial found that head and neck cancer patients who gargled with hydrogen water had significantly better oral mucositis scores and lower pain by day fourteen of treatment, compared to patients who gargled with plain water. Quality-of-life scores improved too, though a separate frailty measure in the same trial didn't show a significant difference. That's one pilot study, not a large confirmatory trial — the researchers themselves called it exploratory — but it's a specific, recent human result gathered with a rinse that's simple enough to keep up through a multi-week course of treatment.

Does drinking hydrogen water interfere with radiation treatment working?

No published trial has reported that. A 2011 randomized trial in liver radiotherapy patients specifically checked tumor response between the hydrogen-rich water group and the placebo group and found no difference — the antioxidant effect on healthy tissue didn't blunt the treatment's effect on the tumor.

Can hydrogen water replace my radiation oncologist's supportive care recommendations?

No. Nothing in this research suggests hydrogen water should replace standard supportive care during radiation therapy. Always follow your oncology team's guidance, and mention any new wellness habit — including hydrogen water — to your care team before starting it.

Is the research on hydrogen water and radiation therapy new?

Parts of it aren't. The first human quality-of-life trial dates to 2011, and independent review teams have been publishing on hydrogen's radioprotective potential since at least 2020. What's new is a 2026 trial testing a specific, narrower application — gargling for oral mucositis — plus a growing set of independent reviews reaching a consistent conclusion: a safe radioprotective profile across animal and human research, with mechanism still being worked out.

Is hydrogen water the same thing as a radioprotective drug?

No. Hydrogen water is being studied as a research direction, not marketed or regulated as a radioprotective drug. Reviewers describe it as a candidate worth further investigation, not an approved therapy — the distinction between "actively studied" and "clinically approved" matters, and this article is careful to keep them separate throughout.

Where can I read the actual studies instead of a summary?

Every trial and review discussed above is linked by PMID in the References and Further Reading sections below, each pointing directly to its PubMed listing. Reading the original abstract — sample size, methodology, and all — is always the most reliable way to judge a finding for yourself.

Further Reading

For the broader literature, see PubMed's results for hydrogen-rich water and radiotherapy.

• Kang KM et al. (2011), Medical Gas Research. PMID: 22146004. The first randomized human trial testing hydrogen-rich water in radiation oncology patients — better quality-of-life scores during liver radiotherapy, with no change in how well the tumor responded to treatment.
• Hirano SI et al. (2021), International Journal of Molecular Sciences. PMID: 33925430. A review concluding that animal and clinical research point to a consistently safe radioprotective effect, working through several mechanisms beyond simple antioxidant activity.
• Hu Q et al. (2020), Biomedicine & Pharmacotherapy. PMID: 32763820. An independent review reaching a similar conclusion — good radioprotective potential — while calling for more research before treating the question as settled.
• Zhou W et al. (2024), Journal of Cancer Research and Clinical Oncology. PMID: 38555538. A review exploring hydrogen's potential role across cancer prevention and treatment research, including its proposed effects on immune cell function during treatment.
• Xiao HW et al. (2018), Experimental & Molecular Medicine. PMID: 29371696. An animal study finding hydrogen-water reduced radiation-induced gut injury in mice — early-stage evidence for the abdominal and pelvic radiation side of this research.
• Dhillon G et al. (2024), International Journal of Molecular Sciences. PMID: 38256045. A systematic review of 25 hydrogen water studies spanning exercise, liver function, cardiovascular health, and more — useful context for how this radiotherapy research fits into the wider field.

References

1. Ohsawa I, Ishikawa M, Takahashi K, et al. Hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals. Nature Medicine. 2007;13(6):688-694. PMID: 17486089. DOI: 10.1038/nm1577
2. Kang KM, Kang YN, Choi IB, Gu Y, Kawamura T, Toyoda Y, Nakao A. Effects of drinking hydrogen-rich water on the quality of life of patients treated with radiotherapy for liver tumors. Medical Gas Research. 2011;1(1):11. PMID: 22146004. DOI: 10.1186/2045-9912-1-11
3. Tsai HT, Huang CJ, Wang HC, Luo SD, Rau KM, Chou PL. Effects of Hydrogen Water Gargling on Oral Mucositis and Pain in Head and Neck Cancer Patients: A Randomized Controlled Pilot Study. Integrative Cancer Therapies. 2026;25:15347354261463550. PMID: 42338291. DOI: 10.1177/15347354261463550
4. Xiao HW, Li Y, Luo D, Dong JL, Zhou LX, Zhao SY, Zheng QS, Wang HC, Cui M, Fan SJ. Hydrogen-water ameliorates radiation-induced gastrointestinal toxicity via MyD88's effects on the gut microbiota. Experimental & Molecular Medicine. 2018;50(1):e433. PMID: 29371696. DOI: 10.1038/emm.2017.246
5. Hirano SI, Ichikawa Y, Sato B, Yamamoto H, Takefuji Y, Satoh F. Molecular Hydrogen as a Potential Clinically Applicable Radioprotective Agent. International Journal of Molecular Sciences. 2021;22(9):4566. PMID: 33925430. DOI: 10.3390/ijms22094566
6. Hu Q, Zhou Y, Wu S, Wu W, Deng Y, Shao A. Molecular hydrogen: A potential radioprotective agent. Biomedicine & Pharmacotherapy. 2020;130:110589. PMID: 32763820. DOI: 10.1016/j.biopha.2020.110589
7. Zhou W, Zhang J, Chen W, Miao C. Prospects of molecular hydrogen in cancer prevention and treatment. Journal of Cancer Research and Clinical Oncology. 2024;150(4):170. PMID: 38555538. DOI: 10.1007/s00432-024-05685-7
8. Dhillon G, Buddhavarapu V, Grewal H, Sharma P, Verma RK, Munjal R, Devadoss R, Kashyap R. Hydrogen Water: Extra Healthy or a Hoax?-A Systematic Review. International Journal of Molecular Sciences. 2024;25(2):973. PMID: 38256045. DOI: 10.3390/ijms25020973

Holy Hydrogen products, including the Lourdes Hydrofix Premium Edition, are not medical devices and are not intended to diagnose, treat, cure, or prevent any disease. All information on this site is provided for educational and general wellness purposes only and should not be considered medical advice. Always consult a qualified healthcare provider before beginning any new wellness practice, especially if you have a medical condition, are pregnant or nursing, or take prescription medications.