Pulse of Oriental Medicine: Alternative Medicine That Works for Regular Folks
Alternative Medicine That Works for Regular Folks



Are My Herbs and Drugs Dangerous Together?
Drug Herb Interactions

by Brian B. Carter, MS, LAc

Brian is the founder of the Pulse of Oriental Medicine. He teaches at the Pacific College of Oriental Medicine and maintains a private acupuncture and herbal practice in San Diego, California, and is the author of Powerful Body, Peaceful Mind: How to Heal Yourself with Foods, Herbs, and Acupressure.

Also see, "How to Determine If You Can Take Herbs with Your Drugs."

Negative drug-herb interactions (side effects as the result of taking drugs and herbs at the same time) have been over-hyped because of fear, lack of knowledge and sheer speculation. Although there are some negative interactions, research has also discovered positive interactions between drugs and herbal formulas.

Drug-drug interactions are a much more serious problem than either herb-drug or herb-herb interactions. This is because drugs are high doses of single, active, unstable chemicals, while herbs contain multiple ingredients, some of which are natural buffers.

Chinese herbal formulas are even more broad, comprehensive, and balanced than single western herbs. (When I talk about western herbs, I mean many of the single herbs you can buy in stores which are part of the western herbal tradition... and were not part of the chinese herbal tradition.)


Article Contents:

Which is Safer - Single Herbs or Herb Formulas?

Herbal formulas are safer. The more singular a substance is, the more likely it is to cause side effects and interact with other substances. Studies bear this out- a number of them indicate that drugs negatively interact more with single herbs than they do with herbal formulas.

From most dangerous to safest (in order) are these cominations:

Type of Combination
Situation and Results
1. Multiple drugs The result of one or more physicians prescribing you one or more drug; interaction range from discomfort to life-threatening.
2. Drugs + single western herbs 1 or more physician-prescribed drugs + you buy yourself 1 or more single herbs
3. One drug alone Can still have mild to strong side effects
4. One herb alone
Mild side effects are possible
5. Multiple single wester herbs
You buy several herbs for yourself and they may interact, especially if the combination is not based on tradition or research
6. Drug + herb formula
Prescribed by both a western and chinese-style physicians; based on research and guesswork. The results of such studies have been positive. The appropriate formula is often able to balance out the drug's side effects and/or boost its effectiveness

7. Single western herb + chinese herb formula

Again based partly on tradition and partly guesswork. Some unexpected interactions are possible but should be mild.
8. Personalized chinese herbal formula alone Based on diagnosis, tradition, and research. There should be little or no unexpected interactions or side effects, and if there are, the physician can modify the formula to better suit you.

Our current habit of purchasing single herbs like ginseng and gingko (amateur self-prescription) is more dangerous than seeing an acupuncturist for a personalized chinese herbal formula. Did you know that at least 6 million people in the U.S. take ginseng singly? (Read more on ginseng) Also read number 10 in the next section...

In addition, when you take several drugs and several single herbs, there are many more potential interactions... that real-world situation is more complex than any of our research has investigated. So, it's a good rule of thumb to take as few drugs and single herbs as possible.

The safest therapy options are just about the reverse order of the list above... in order from most to least safe:

  1. Personalized Chinese Herbal Formula
  2. Single western herb + chinese herb formula
  3. Drug + herb formula (this is probably more effective than #2, but possibly more dangerous)
  4. Multiple single western herbs
  5. One herb alone
  6. One drug alone
  7. Drugs + single western herbs
  8. Multiple drugs

These are not hard and fast rules. In some situations, multiple drug therapy is the best choice... I urge you to review your options with your western and chinese-style physicians, and together you can all make the best decision.

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Negative Drug Herb Interactions

1. Pain Medications

Sometimes herbs and acupuncture can neutralize the effect of pain drugs. For example, patients on neurontin or morphine need to be treated differently. Acupuncture in these patients should be of shorter duration with less stimulation and subtler point selections (like eight extra points, e.g.). Moxibustion is a helpful alternative.

2. Chinese Licorice

Gan cao (chinese licorice) is sometimes problematic… it is in many herb formulas, but in low dosages. Higher dosages can lead to fluid retention. Gan cao can also reduce the absorption of oral tetracycline and some other meds, and can offset the pharmacological effect of spironolactone. The rule of separating the dosage times of herbs and drugs solves this problem.

3. Tannins

Tannins are insoluble with antibiotics. A few herbs such as Da Huang (rhubarb), He Zi, and Mo Yao (Myrrh) contain tannins. Tannic acids may inhibit the absorption of iron.

4. Glycosides

Glycosides, which are active ingredients in many herbs, are neutralized by acidic drugs. That means that, for example, Vitamin C (ascorbic acid) and nicotinic acid could prevent your herbs from working.

5. Blood-thinners

Patients on warfarin (coumadin) are most at risk for problems from drug-herb interactions. Warfarin is given to thin the blood, thus preventing the likelihood of clots blocking blood vessels in the heart, lungs, or brain. Warfarin's dosage needs to be quite exact to work, so we don't want any herbs affecting it. Herbs and herbal formulas that contain blood movers must be avoided. This includes, among others, herbs dan shen (salvia), dang gui (angelica), and yan hu suo (corydalis), and herb formulas like xue fu zhu yu tang, di dan tang, and tao he cheng qi tang. Feverfew, garlic, Ginkgo, ginger, and ginseng may alter bleeding time, and so they also should be avoided by patients on warfarin.

6. Dan Shen (Salvia)

Salvia (see #5) can also reduce the effectiveness of anti-ulcer drugs.

7. Surgery and Herbs

It's a good idea to stop taking herbs 5 days before surgery, and then after surgery take herbs only to rebuild the body.

8. Drugs for the Heart

Ma Huang (ephedra) should not be taken (even in an herbal formula) if your are on digitalis or any other heart drugs. It also reduces the effectiveness of anti-anxiety and sedative drugs, and increases the cardiovascular effects of caffeine. Kyushin, gan cao (licorice), plantain, uzara root, shan zha (hawthorn), and ren shen (ginseng) may interfere with digoxin.

9. St. John's Wort

Studies have shown that patients who take St. John's Wort while on a Selective Serotonin Re-uptake Inhibiting (SSRI) anti-depressant end up with varying blood levels of drugs. This means it interferes with the effectiveness of your anti-depressant. Because its mode of action is not understood, it should be avoided with monoamine oxidase inhibitors and SSRI's.

It also appears to reduce blood levels of cyclosporin, a drug taken to prevent the body's rejection of transplanted organs. And it reduces the effectiveness of the AIDS drug indinavir. It's not yet clear whether it interferes with the metabolism of all drugs, or just some. It may be difficult for your medications to work effectively if you take St. John's Wort.

10. Ginseng

Ginseng plus phenelzine sulfate may cause headache, tremulousness, and manic episodes. Ginseng should not be used with estrogens or corticosteroids.

11. Valerian

Valerian should not be combined with barbituates.

12. Kelp

Kelp as a source of iodine may interfere with thyroid replacement therapies.

13. Echinacea

Echinacea could cause liver toxicity and therefore should not be used with other known liver toxic drugs, such as anabolic steroids, amiodarone, methotrexate, and ketoconazole

14. Nonsteroidal anti-inflammatory drugs may negate the usefulness of feverfew in the treatment of migraine headaches

15. Kava when used with alprazolam has resulted in coma

16. Evening primrose oil and borage should not be used with anticonvulsants because they may lower the seizure threshold.

17. Both Rhubard and Aloe cause loss of potassium through the stool... this may increase the side effects of cardiac glycosides and antiarrhythmic drugs.

18. Astragalus (huang qi) may oppose immunosupressive drugs, because it tends to improve immune function.

Some of these herbs are not chinese herbs (feverfew, gingko, valerian, kava, echinacea, everning primrose, borage). If you saw a Chinese herbalist, they wouldn't be an issue. Plus, chinese herbalists prescribe more balanced formulas, not single herbs, so potential interactions with the single herbs are reduced.

Positive Drug Herb Interactions

  1. Gan cao increases the effectiveness of prednisone. This benefit can be used to reduce the dosage of prednisone in patients who have to take it long term. This reduces the serious long-term side effects (bone density loss, adrenal insufficiency, etc.).
  2. In typhoid fever, research showed that those given an herbal formula (xue yang mei) plus a sulfa drug did better than those just given the sulfa drug. Both groups had a 100% cure rate, but the combination group experienced few or no side effects.
  3. In mastitis, those given a heat and toxin clearing herbal formula (jin yin hua, pu gong ying, yu jin, chi shao, dan shen, qing pi) plus penicillin/streptomycin injections did much better than those only given the injection.
  4. In adult primary nephrotic syndrome, one group was simply given corticosteroids, while another group was also given an herb formulas (dan shen, di gu pi, gui ban, han lian cao, hong hua, nu zhen zi, gou qi zi, sheng di, zhi mu). The steroid only group had a recovery rate of 56%, while the combined group's recovery rate was 85%. In another study with nephritic patients, patients given predisone, zhi mu (anemarrhena), shu di huang (rehmannia), and gan cao (licorice) experienced less of the corticosteroid side effects.
  5. Late-stage gastric cancer patients were studied. All patients were given a drug chemotherapy combo of either methotrexate, fluoroacil and vinblastine, or methotrexate, MFC, and fluorocil. One of the two groups was also given herbs (huang qi, tai zhi shen, caulis banthalobi, ji xue tang, bai zhu, fu ling, niu zhen zi, gou qi zi, tu su zi). Side effects were cut in half or eliminated in the chemo plus herbs group. Here's a table of the percentage of patients who experienced specific side effects:
Side Effect

Chemo Only

Chemo & Herbal Formula
Loss of Appetite 50% 19%
Nausea and vomiting 50% 19%
Diarrhea 50% 0%
Fatigue 67% 31%
Numbness in Limbs 33% 0%

Solving the Multi-Drug Problem with Herbs

Many patients are on multiple drugs. We have had success reducing these medications over time with the assistance of herbal formulas. An appropriate herbal formula is begun weeks or months ahead of time. This gives the patient a 'cushion,' so to speak. Then the drug dosage is slowly reduced. The herbal prescription is modified as the patient progresses. MD's often cooperate with us in this effort since they know as well as anyone the dangers of poly-pharmacy (taking multiple drugs at once)… especially in the elderly. They say a good geriatric doctor stops more medications than he starts.

Herbs are more likely to correct an imbalance permanently (we call that "healing"). Drugs' therapeutic effects are almost always temporary. It takes more time to do this with herbs… but it's worth it.

Other Situations that are Helped by Herbal Formulas:

Quitting HRT

Instead of just stopping cold (or hot, as the case may be), an herbal formula such as zhi bai di huang wan may be given weeks or months ahead of time. Then the patient's system is more balanced when the HRT is stopped, and rebound symptoms are less likely and less severe.

Breaking the Antibiotic Cycle

Some patients perpetually take round after round of antibiotics. Approaches based on the Shang Han Lun (Cold Damage Classic) such as use of the herb formula Xiao Chai Hu Tang (Minor Bupleurum) have been known to get the patient well and away from the constant need for antibiotics.

Complementing Diuretic Therapy

While Chinese Herbs should never be used to add to the diuretic effect of concurrent drug therapy, they can boost the system. Diuretic drugs reduce the excess fluids, but they do not solve the underlying deficiency. Herbal formulas can be prescribed to strengthen the Spleen and Kidney systems.

Quitting SSRI Anti-Depressants

Of course this can be dangerous, and should be done with a psychiatrist and an herbalist. Herbs such as St. John's Wort (SJW) could be used as a cushion while quitting. SJW does not replace SSRI's… studies show that it must have some other mode of action. Herbal formulas are better anyway. See a Chinese Herbalist.

Quitting Corticosteroids...

As we saw in positive interaction #4 above, herbal formulas can be used in conjunction with corticosteroid treatment (for conditions like lupus, rheumatoid arthritis, primary nephrotic syndrome, etc.). A chinese herbal formula, Bupleurum and Hoelen Combination (Chai Ling Tang) can be used for withdrawal from corticosteroid therapy. Subsequently, it can be used in place of the steroids for continued treatment.

General Rules for Taking Herbs, Vitamins and Drugs:

  1. Take them at different times. Most drugs are taken with meals to limit Stomach irritation. Take herbs between meals (at least 1 hour before and after a meal…2-3 hours would be best) for optimal digestion.
  2. Don't take ascorbic (vitamin C) or salicylic acid (aspirin) at the same time as herbs. The acids will neutralize many of the saponins. Vit C will alter and neutralize herbs… so don't drink any orange or citrus juices with herbs either.
  3. Don't take herbs that are supposed to do the same thing as a drug you're on. For example, don't take blood movers like dan shen or dang gui with warfarin. Don't take diuretics like fu ling with diuretic drugs.
  4. You can take an herbal formula to complement the drugs you have to take. This can reduce or eliminate side effects. It really requires a professional… see a Chinese Medicine practitioner. This works well in chemotherapy to protect the body. However, in Hepatitis C, the interferon/ribavirin treatment requires some of the uncomfortable symptoms of fever and feeling ill to work. Stopping those side effects with herbs has been known to inhibit the drugs' effects. In the case of Hep C, you can opt for Chinese Herbal therapies instead of the western drug cocktail.


  1. (I must first acknowledge a great debt to Z'ev Rosenberg, LAc who is Chair of the Herbal Department at the Pacific College of Oriental Medicine. Many of these ideas come from his lectures there.)
  2. Kelvin Chan, Lily Cheung. Interactions Between Chinese Herbal Medicinal Products and Orthodox Drugs. Dunitz Martin Ltd. 2000. (Most of the positive drug-herb studies mentioned above were summarized in this source. At least one of them came from the Beijing Journal of Traditional Chinese Medicine.)
  3. Miller LG. Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med. 1998 Nov 9;158(20):2200-11. Review.
  4. Dharmananda, S. The Interactions of Herbs and Drugs. June, 2001. Institute for Traditional Medicine. http://www.itmonline.org.

All information herein provided is for educational use only and not meant to substitute for the advice of appropriate local experts and authorities.
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