Natural Remedies and Supplements for Side Effects: What’s Backed by Evidence

Posted By John Morris    On 21 Dec 2025    Comments (15)

Natural Remedies and Supplements for Side Effects: What’s Backed by Evidence

People turn to natural remedies and supplements hoping to avoid the side effects of prescription drugs. Maybe you’re taking something for anxiety, menopause, or chronic pain-and you think adding an herb like black cohosh or St. John’s wort will help smooth things out. But here’s the problem: natural doesn’t mean safe. And in many cases, these so-called gentle solutions can make things worse.

Why ‘Natural’ Doesn’t Mean Safe

The idea that plants or herbs are harmless because they come from nature is deeply rooted. But the truth is, plants produce chemicals for a reason-to defend themselves. Those same chemicals can affect your body in powerful, sometimes dangerous ways.

Take ephedra. It was once sold as a weight-loss aid and energy booster. Between 1995 and 1999, the FDA logged over 800 reports of serious side effects from ephedra, including heart attacks, strokes, and even death. Half of those cases happened in people under 40. The FDA banned it in 2004. But similar products still pop up under different names, and people keep using them thinking, “It’s just a plant.”

Herbal supplements aren’t tested like prescription drugs. Under U.S. law (DSHEA, 1994), companies don’t need to prove safety or effectiveness before selling them. That means what’s on the label might not be what’s inside. A 2015 study found that nearly 20% of herbal products contained contaminants-heavy metals, pesticides, or even hidden prescription drugs. One product marketed as “natural ginseng” was found to contain a powerful steroid. Another “turmeric supplement” had traces of lead.

Common Supplements and Their Real Risks

Some supplements get a lot of attention for helping with side effects. But the evidence is mixed-and the risks are real.

Black cohosh is often used for hot flashes during menopause. Some studies suggest it might help, but only if it’s a specific, standardized brand like Remifemin®. Other versions? No proof they work. And while early fears about liver damage were based on weak evidence, the Cleveland Clinic still warns: if you start feeling nauseous, your skin turns yellow, or you’re unusually tired after taking it, stop. Liver injury from black cohosh is rare-but it happens.

Echinacea is another popular one, often taken to prevent colds. Most research says it doesn’t reduce how often you get sick. But it can cause allergic reactions-especially if you’re allergic to ragweed, daisies, or chrysanthemums. People with autoimmune diseases like lupus or MS should avoid it entirely. It can trigger flare-ups.

St. John’s wort is used for mild depression. But here’s the catch: it changes how your body processes other drugs. It can make birth control pills fail. It can reduce the effectiveness of antidepressants, HIV meds, and even some cancer treatments. One study found it lowered blood levels of birth control pills by up to 24%. That’s not a small risk. It’s life-changing.

Ginkgo biloba and cranberry are both marketed as “blood thinners” for heart health. But if you’re already on warfarin or aspirin, combining them can lead to dangerous bleeding. One case report described a 72-year-old man who started taking ginkgo and ended up in the ER with a brain bleed. He wasn’t told it could interact with his blood thinner.

Liquorice root is in about 75% of traditional Japanese herbal formulas. It sounds harmless, right? But it can cause pseudohyperaldosteronism-a condition that makes your body hold onto salt and lose potassium. Symptoms: high blood pressure, swelling, muscle cramps, and even seizures. The NHS says up to 3% of people who take it regularly develop this. And it’s not just tea. It’s in candies, throat lozenges, and supplements.

Who’s at Highest Risk?

Not everyone reacts the same way. Some people are far more vulnerable.

Older adults process herbs slower. As we age, our liver and kidneys don’t clear toxins as efficiently. That means even a normal dose of an herb can build up to dangerous levels. A 65-year-old taking black cohosh or ginkgo might be at twice the risk of a 30-year-old.

People on multiple medications are walking a tightrope. A 2023 review found that nearly 60% of adults over 65 take at least five prescription drugs. Add in a few supplements, and the chance of a bad interaction skyrockets. St. John’s wort doesn’t just affect birth control-it can interfere with cholesterol meds, blood pressure pills, and even chemotherapy.

People with liver or kidney disease should avoid most herbal supplements altogether. The liver is where most herbs are broken down. If it’s already struggling, adding even a “safe” herb can push it into failure. One study found that herbal products were responsible for 20% of acute liver injury cases in the U.S. between 2004 and 2013. And in over half of those cases, the herb itself wasn’t the problem-it was contamination or mislabeling.

Herbal supplement bottles leaking toxic smoke that forms monstrous shapes representing organ damage.

What About the Benefits? Is Anything Proven?

Yes-but only in specific cases, and only with the right product.

The Natural Medicines Database, one of the most respected sources for supplement evidence, gives only a few herbs a “possibly effective” rating. Black cohosh (for menopause) is one. Ginger (for nausea during pregnancy) is another. Peppermint oil (for IBS) has decent support. But even these come with caveats: dosage matters. Brand matters. Timing matters.

And here’s the kicker: most supplements have no proven benefit for preventing or reducing side effects from prescription drugs. If you’re on chemo and taking turmeric to “reduce inflammation,” you’re not protecting yourself-you might be interfering with treatment. Studies show some antioxidants can blunt the effect of radiation and certain chemo drugs.

How to Use Supplements Safely

If you’re considering a supplement, here’s what to do:

  1. Talk to your doctor or pharmacist first. Not your friend. Not your yoga instructor. Your medical professional. Tell them everything you’re taking-even if you think it’s “just a tea.”
  2. Check for interactions. Use a trusted tool like the Mayo Clinic’s drug interaction checker or ask your pharmacist. St. John’s wort? Ginkgo? Garlic? They all have dangerous combos.
  3. Buy from reputable brands. Look for third-party testing seals: USP, NSF, or ConsumerLab. These don’t guarantee safety, but they do check for what’s actually in the bottle.
  4. Start low, go slow. Even if something seems safe, begin with half the recommended dose. Watch for changes in sleep, digestion, mood, or energy.
  5. Stop if something feels off. New headache? Nausea? Rash? Dizziness? Don’t assume it’s “just adjusting.” It could be your body reacting to something harmful.
  6. Report side effects. If you have a bad reaction, file a report with the FDA’s Safety Reporting Portal. It helps others stay safe.
Older adults at a table with transparent body showing dangerous herb-drug interactions.

The Bigger Picture: Regulation Is Broken

The U.S. treats supplements like food. Europe treats them like medicine. In the EU, herbal products need to prove traditional use and safety before being sold. In the U.S.? No such requirement. That’s why you can buy a “natural sleep aid” online that contains melatonin, valerian, and a hidden sedative-all in one capsule.

There’s hope, though. Scientists are using DNA barcoding to catch fake herbs. Labs are getting better at spotting contaminants. The European Medicines Agency’s herbal monograph system is being studied as a model for the U.S.

But until regulations catch up, you’re on your own. And the burden of proof isn’t on the company. It’s on you.

Bottom Line: Be Informed, Not Hopeful

Natural remedies aren’t evil. Some can help. But they’re not harmless. They’re powerful. And they can interact with your body-and your medications-in ways you can’t predict.

If you’re taking a prescription drug and thinking about a supplement to manage side effects, pause. Ask: Is there real evidence this works? Is there real evidence it’s safe with what I’m already taking? And most importantly-have I talked to my doctor?

The truth isn’t sexy. It doesn’t come in a bottle labeled “100% Pure.” But it’s the only thing that will keep you safe.

Can natural supplements really help with side effects from prescription drugs?

Very few have solid evidence. Ginger can help with nausea from chemo. Black cohosh may reduce hot flashes-but only specific brands. Most others, like echinacea or turmeric, don’t reliably reduce side effects. And many can make things worse by interacting with your meds. Don’t assume they’re helpful just because they’re natural.

Are herbal supplements safer than prescription drugs?

No. Prescription drugs go through years of testing for safety and dosage. Herbal supplements don’t. In fact, herbal products cause more liver injuries in the U.S. than many prescription medications. The difference isn’t safety-it’s oversight. Just because something is plant-based doesn’t mean it’s gentle on your body.

What’s the most dangerous supplement people don’t realize is risky?

St. John’s wort. It’s sold as a “natural antidepressant,” but it can make birth control fail, reduce the effectiveness of antidepressants, HIV meds, and even chemotherapy drugs. People think it’s harmless because it’s herbal. But it’s one of the most dangerous supplements for drug interactions-and most users have no idea.

Can I trust supplements labeled as “USP Verified” or “NSF Certified”?

Yes, these labels mean the product was tested for what’s on the label and for contaminants. They don’t guarantee effectiveness or safety with your meds-but they do mean you’re less likely to get a bottle filled with sawdust or lead. Look for these seals. Avoid anything without them.

Why do some people say supplements helped them while others had bad reactions?

Because everyone’s body is different. Genetics, age, liver health, other meds, and even gut bacteria affect how you respond. One person might take ginkgo and feel sharper. Another might bleed internally. That’s why blanket claims like “this herb helps everyone” are misleading. What works for one person can harm another.

Should I stop my supplements before surgery?

Absolutely. Herbs like ginkgo, garlic, ginger, and fish oil can increase bleeding risk. Others, like valerian or kava, can interfere with anesthesia. Most surgeons ask you to stop all supplements at least two weeks before surgery. Don’t assume they know what you’re taking-tell them everything.

Is it safe to take herbal supplements while pregnant?

Most aren’t. Even common ones like chamomile, peppermint, or licorice can affect hormones or blood flow. Ginger is one of the few with evidence for morning sickness-but only in small doses. Always check with your OB-GYN before taking anything, even tea.

What should I do if I think a supplement caused a side effect?

Stop taking it immediately. Contact your doctor. Then report it to the FDA’s Safety Reporting Portal at safetyreporting.hhs.gov. Your report helps regulators track dangerous products and protect others. Don’t wait-side effects can be serious, and many go unreported.

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