Patient Handout: Safe Use of Herbal Supplements
Critical Safety Message
Herbal supplements are not FDA-regulated for safety or effectiveness before they reach store shelves, meaning their content, purity, and potency are unpredictable—you should assume they carry risks similar to prescription medications and discuss all supplement use with your healthcare provider before starting them. 1, 2
Why You Must Tell Your Doctor About Supplements
- Most patients (one-third) do not inform their physicians about supplement use, yet this information is critical for your safety. 3
- Supplements can cause serious drug interactions, organ damage, allergic reactions, and even death—they are not inherently safer just because they are "natural." 2, 4
- Your doctor cannot protect you from dangerous interactions if they don't know what you're taking. 5
Supplements That Are Dangerous and Should Be Avoided
St. John's Wort: High-Risk Supplement
St. John's wort causes dangerous interactions with numerous medications and should be discontinued at least 2 weeks before any surgery. 6
- Reduces effectiveness of: Birth control pills (causing unintended pregnancy), antidepressants (SSRIs, MAOIs—risk of serotonin syndrome), blood thinners, immunosuppressants (organ rejection risk), HIV medications, chemotherapy drugs, and heart medications. 6
- If you take ANY of these medications, do not use St. John's wort. 6
Beta Carotene: Proven Harm
Beta carotene supplements increase lung cancer risk and death rates in smokers—avoid them entirely if you smoke. 1
- Good evidence shows beta carotene provides no benefit for cancer or heart disease prevention and causes harm in smokers. 1
Supplements Requiring Caution
Ashwagandha
- Has sedative properties that can dangerously enhance the effects of sleeping pills, anxiety medications, pain medications, and anesthesia. 7
- Consider stopping 2 weeks before any planned surgery. 7
- Not FDA-regulated, so product quality varies unpredictably between brands. 7
Other Common Supplements with Drug Interactions
- Ginkgo and ginseng: Implicated in multiple interaction reports, though many are unsubstantiated. 8
- Garlic, green tea extract, kava kava: May interact with specific medications but are safer with others—requires individual assessment. 5
When Supplements Are NOT Needed
Without documented nutritional deficiencies, vitamin and mineral supplements add cost and medication burden without proven benefit for preventing cancer, heart disease, or cognitive decline. 1, 2
- Multiple daily vitamins contribute to medication complexity in older adults without substantiated benefit. 1
- Exceptions where supplements ARE recommended: Folic acid for women planning pregnancy, calcium for bone health in older adults, vitamin D for documented deficiency. 1
Special Populations at Higher Risk
Pregnant Women
Avoid all herbal supplements during pregnancy—there are no rigorous safety studies, and active plant chemicals can harm the developing fetus. 9
- The Teratology Society states it should not be assumed that dietary supplements are safe for the embryo or fetus. 9
Older Adults Taking Multiple Medications
- Supplements increase risk of drug interactions, falls, confusion, and hospitalizations in elderly patients on multiple medications. 1, 2
Before Surgery
- Many supplements affect bleeding, anesthesia, and wound healing. 1
- Disclose all supplement use during your preoperative visit, typically 2+ weeks before surgery. 1
Quality Control Problems You Should Know
- Herbal products may contain unlisted ingredients, contaminants, adulterants, or even hidden prescription drugs (like steroids). 1
- The FDA only responds to safety problems AFTER products are already on the market and causing harm. 3
- Products with a U.S. Pharmacopeia (USP) seal have better quality control, but imprecision in content still poses risks. 1
What to Do Instead of Taking Supplements
Prioritize eating a diet high in fruits, vegetables, whole grains, and legumes rather than relying on supplements for nutrition. 1, 2
- Taking vitamins does not replace the need for a healthy diet. 1
- Foods containing nutrients naturally (like beta carotene in vegetables) are safe, unlike high-dose supplements. 1
Action Steps for Safe Supplement Use
- Tell every healthcare provider about ALL supplements you take—bring bottles to appointments. 1, 2
- Never start a supplement without discussing it with your doctor first, especially if you take prescription medications. 5
- If you choose to take supplements despite lack of proven benefit, stick to recommended dietary reference intake doses—higher doses of vitamins A and D can be harmful. 1
- Report any side effects from supplements to the FDA MedWatch system (your doctor can help with this). 3
- Stop all herbal supplements at least 2 weeks before any planned surgery unless your surgeon specifically approves continuation. 1, 6
Red Flags: When to Stop Supplements Immediately
- You are prescribed a new medication (check for interactions first). 5
- You are planning pregnancy or discover you are pregnant. 9
- You are scheduled for surgery. 1
- You develop new symptoms after starting a supplement (allergic reactions, liver problems, bleeding). 4
- You smoke and are taking beta carotene. 1
Bottom Line
The safest approach is to avoid herbal supplements unless you have a documented nutritional deficiency requiring treatment under medical supervision—supplements carry real risks without proven benefits for most people. 1, 2