Patient Handout for Herbal Supplements
Critical Safety Warning
Herbal supplements are not regulated by the FDA for purity, potency, or safety before they reach the market, meaning the actual content and strength of these products is often unclear and varies widely between brands. 1, 2
Why You Must Tell Your Doctor About ALL Supplements
- Only 33% of supplement users disclose their use to healthcare providers, creating dangerous gaps in your care. 3
- Many supplements interact with prescription medications, reducing their effectiveness or causing serious side effects. 1, 4
- Healthcare providers cannot protect you from dangerous interactions if they don't know what you're taking. 2
- Tell every doctor, surgeon, and pharmacist about ALL vitamins, herbs, teas, and natural products you use—not just prescription medications. 5
Supplements You Must STOP Before Surgery
Discontinue these at least 2 weeks before any surgical procedure: 1
Bleeding Risk Supplements
- Ginkgo - Decreases blood clotting and interacts with warfarin 6
- Ginger - Reduces platelet aggregation 6
- Garlic - Has antiplatelet effects 6, 5
- Turmeric - Inhibits multiple clotting factors 6
- Vitamin E - Antiplatelet effects, especially dangerous with aspirin 6
- Bromelain - Increases bleeding risk 6
- Saw palmetto - Antiplatelet effects 5
Drug Interaction Supplements
- St. John's Wort - Reduces effectiveness of pain medications, birth control, antidepressants, HIV medications, chemotherapy, and immunosuppressants 6, 7, 5
- Goldenseal - Multiple drug interactions through liver enzymes 6
- Grapefruit extract - Unpredictably increases blood levels of many medications 6, 5
Blood Pressure/Heart Rate Supplements
- Licorice root - Causes fluid retention and low potassium 6
- Yohimbine - Causes dangerous blood pressure changes 6
- Horny goat weed - Causes blood vessel dilation 6
Sedation Risk Supplements
- Kava - Excessive sedation with anesthesia and pain medications 6, 5
- Lemon balm - Additive sedation with anesthetics 6
Blood Sugar Supplements
- Black seed oil, alpha-lipoic acid, American ginseng, chromium, fenugreek, Panax ginseng - All affect blood sugar control during surgery 5
Never Use These
- Kratom - Has opioid-like properties; FDA explicitly warns against use 6
- Marijuana/Cannabis - Impairs platelet function and has multiple drug interactions 6
- Garcinia cambogia - Associated with liver toxicity 5
Supplements Safe to Continue
These can be taken up to and including the day of surgery: 6
- Melatonin - May reduce anxiety and delirium 6
- German chamomile - Reduces anxiety safely 6
- Passionflower - Anxiolytic with good safety profile 6
- Lavender - Safe for anxiety 6
- Valerian - Safe and may protect brain function 6
- Omega-3/Fish oil - Explicitly safe to continue 6, 5
Dangerous Drug Interactions You Must Know
St. John's Wort Interactions
This supplement reduces the effectiveness of: 7, 5
- Birth control pills (can cause unintended pregnancy)
- Antidepressants (SSRIs, MAOIs—risk of serotonin syndrome)
- Blood thinners
- HIV medications
- Chemotherapy drugs
- Immunosuppressants (cyclosporine, tacrolimus)
- Heart medications
If you take ANY of these medications, do NOT use St. John's Wort. 7
Grapefruit Interactions
- Avoid grapefruit completely if you take statins or cyclosporine—do not just separate timing of ingestion. 5
- The effect is unpredictable, long-lasting, and can cause dangerous increases in medication levels. 5
Black Seed Oil Interactions
- Increases risk of low blood sugar when combined with metformin, sulfonylureas, or insulin—check blood sugar more frequently. 5
- May cause low blood pressure when combined with ACE inhibitors (lisinopril, enalapril)—monitor blood pressure closely. 5
Special Populations at Higher Risk
If You Are Pregnant or Breastfeeding
- Many herbal supplements can harm your baby or affect milk production. 8, 9
- 7-55% of pregnant women use herbal supplements, often assuming they are safer than prescription medications—this is false. 8
- Tell your obstetrician about every supplement you use. 8
- If a supplement is not critical to your health, defer use during pregnancy and breastfeeding. 9
If You Have Chronic Kidney Disease
- Review ALL supplements with your nephrologist—many require dose adjustments or must be avoided. 1
- Over-the-counter products and herbal remedies may be harmful with kidney disease. 1
If You Have Diabetes
- Many supplements affect blood sugar unpredictably—chromium, potassium, magnesium, and zinc can all impact glucose control. 1
- There is insufficient evidence that individual herbs improve diabetes management. 1
- Herbal preparations can interact with diabetes medications. 1
If You Have High Blood Pressure
- Avoid Ma Huang (ephedra), St. John's Wort with MAO inhibitors, and yohimbine. 1
- These supplements can dangerously elevate blood pressure. 1
If You Take HIV Medications
- Obtain a complete medication history including over-the-counter medications, vitamins, minerals, and herbal remedies before starting HIV treatment. 1
- Products containing calcium, iron, magnesium, or aluminum can reduce absorption of HIV medications. 1
- St. John's Wort significantly reduces HIV medication levels. 7
Signs of Serious Adverse Effects—Seek Immediate Medical Attention
Stop the supplement and call your doctor or go to the emergency room if you experience: 2
- Unusual bleeding or bruising
- Severe allergic reactions (rash, swelling, difficulty breathing)
- Yellowing of skin or eyes (liver damage)
- Severe abdominal pain
- Confusion or altered mental status
- Chest pain or irregular heartbeat
- Severe headache or vision changes
- Signs of low blood sugar (shakiness, sweating, confusion)
- Signs of low blood pressure (dizziness, fainting)
How to Use Supplements Safely
Always tell your healthcare provider about every supplement, vitamin, tea, or natural product you use—bring the bottles to appointments. 5, 2
Never assume "natural" means "safe"—many supplements cause organ damage, interact with medications, or contain toxic contaminants. 1, 2
Stop all supplements with bleeding risk, drug interactions, or sedative effects at least 2 weeks before surgery. 1
Check with your pharmacist before starting any new supplement if you take prescription medications. 4
Be aware that supplement content is not standardized—different brands may contain vastly different amounts of active ingredients. 1
Do not use supplements as a substitute for proven medical treatments without discussing with your doctor. 1
If you develop new symptoms or your medications seem less effective after starting a supplement, tell your doctor immediately—this may indicate a dangerous interaction. 8
Questions to Ask Your Doctor
- Is this supplement safe with my current medications?
- Could this supplement affect my medical conditions?
- Should I stop this supplement before surgery or procedures?
- Are there prescription medications with known safety profiles that could replace this supplement?
- How will we monitor for side effects or interactions?
Key Takeaway
The safest approach is to discuss ALL supplement use with your healthcare team before starting, and to temporarily discontinue supplements before surgery unless your doctor specifically tells you to continue them. 1 Without demonstrated benefit or proven lack of harm, there is little downside to temporarily stopping herbal supplements. 1