Review of Abnormal Laboratory Test Results and Toxic Effects Due to Use of Herbal Medicines

Amitava Dasgupta, PhD


Am J Clin Pathol. 2003;120(1) 

In This Article

Toxic Effects of Herbal Medicines

Many commonly used herbal medicines are toxic. The toxic effects of common herbal products are given in Table 4 . Toxic effects of herbal medicines range from allergic reaction to cardiovascular, hepatic, renal, neurologic, and dermatologic toxic effects. Although ginseng is considered safe, the toxicity of ginseng has been reported in the literature.


In 1979, the term ginseng abuse syndrome was coined as a result of a study of 133 people who took ginseng for 1 month. Most subjects experienced central nervous system stimulation. The effect of ginseng on mood seems to be dose-dependent. At a dose of less than 15 g/d, subjects experienced depersonalization and confusion. At a dose of more than 15 g/d, some subjects experienced depression. Fourteen patients experienced ginseng abuse syndrome, which is characterized by symptoms of hypertension, nervousness, sleeplessness, skin eruption, and morning diarrhea.[71] An episode of Stevens-Johnson syndrome was reported in a 27-year-old man following ingestion of ginseng at a dose of 2 pills for 3 days. The patient recovered after 30 days.[72] Vaginal bleeding has been reported in cases related to ginseng use. Interestingly, 1 patient had undergone a hysterectomy 14 years earlier.[73] There is a case report describing symptoms including insomnia, headache, irritability, and visual hallucinations when phenelzine was taken concurrently with ginseng.[74]

Ginkgo Biloba

Ginkgo biloba is prepared from dried leaves of the ginkgo tree by organic extraction (acetone/water). It is used mainly to sharpen mental focus and to improve diabetes mellitus-related circulatory disorders. It also is used as a remedy for impotence and vertigo. The most common adverse effects of ginkgo are gastric disturbances, headache, and dizziness. Miwa et al[75] reported a case of a 36-year-old woman who had a generalized seizure 4 hours after the ingestion of 70 to 80 gingko nuts.

One commonly reported adverse effect of ginkgo biloba is bleeding. Spontaneous intracerebral hemorrhage occurred in a 72-year-old woman who took 50 mg of ginkgo 3 times a day for 6 months.[76] Fessenden et al[77] reported a case of postoperative bleeding after laparoscopic cholecystectomy. One report described a 70-year-old man with bleeding from the iris into the anterior chamber of the eye 1 week after beginning a self-prescribed regimen of a concentrated ginkgo biloba extract in a dosage of 40 mg twice a day.[78] His only medication was 325 mg of aspirin daily. After the spontaneous bleeding episode, he continued taking the aspirin but stopped taking the ginkgo product. During a 3-month follow-up period, he had no further bleeding episode.[78]


The Australian Adverse Drug Reaction Advisory Committee received 11 reports of adverse reactions associated with echinacea between July 1996 and September 1997. There were 3 reports of hepatitis; 3 reports of asthma; 1 report each of rash, myalgia, and nausea; 1 report of urticaria; and 1 report of anaphylaxis. There are other published reports of echinacea use associated with contact dermatitis and anaphylaxis.[79]


Garlic is promoted for lowering cholesterol and blood pressure levels. Garlic contains various sulfur-containing compounds, which are derived from allicin. Chopped garlic-and-oil mixes left at room temperature can result in fatal botulism food poisoning according to the FDA. Clostridium botulinum bacteria are dispersed throughout the environment but are not dangerous in the presence of oxygen. The spores produce a deadly toxin in anaerobic, low-acid conditions. The garlic-and-oil mixture produces that environment.[80]

Ma Huang (Ephedra-Containing Herbal Diet Pills)

Ma huang (ephedra) is commonly found in herbal weight-loss products that often are referred to as herbal fen-phen, an alternative to fenfluramine, a prescription drug that was withdrawn from the market owing to its toxic effects. Herbal fen-phen products sometimes contain St John's wort and are sold as "herbal Prozac." "Herbal ecstasy" another ephedrine-containing product, can induce a euphoric state. The FDA has strongly advised consumers not to use ephedrine-containing products marketed as alternatives to street drugs. The German Commission E contraindicated use of ephedra by patients with high blood pressure, glaucoma, or thyrotoxicosis. (-) Ephedrine is the predominant alkaloid of ephedra plants. Other phenylalanine-derived alkaloids found are (+) pseudoephedrine, (-) norephedrine, (+) norpseudoephedrine, (+) N-methylephedrine, and phenylpropanolamine. Haller and Benowitz[81] evaluated 140 reports of ephedra-related toxic effects that were submitted to the FDA between June 1997 and March 31, 1999. The authors concluded that 31% of cases were definitely related to ephedra and another 31% were possibly related. Of the reports, 47% involved cardiovascular problems and 18% involved problems with the central nervous system. Hypertension was the single most frequent adverse reaction, followed by palpitations, tachycardia, stroke, and seizure. Ten events resulted in death, and 13 events caused permanent disability. The authors concluded that use of a dietary supplement that contains ephedra may pose a serious health risk.[81]


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