Consumer Reports lists the following supplements to avoid. Many can cause liver damage.
Aconite (aconiti tuber, aconitum, radix aconiti) Uses: Inflammation, joint pain, wounds, gout. Possible dangers: Toxicity, nausea, vomiting, low blood pressure, respiratory-system paralysis, heart-rhythm disorders, death. Comments: Unsafe. Aconite is the most common cause of severe herbal poisoning in Hong Kong.
Bitter Orange (aurantii fructus, Citrus aurantium, zhi shi) Uses: Weight loss, nasal congestion, allergies. Possible dangers: Fainting, heart-rhythm disorders, heart attack, stroke, death. Comments: Possibly unsafe. Contains synephrine, which is similar to ephedrine, banned by the FDA in 2004. Risks might be higher when taken with herbs that contain caffeine.
Chaparral (creosote bush, Larrea divaricata, larreastat) Uses: Colds, weight loss, infections, inflammation, cancer, detoxification. Possible dangers: Liver damage, kidney problems. Comments: Likely unsafe. The FDA advises people not to take chaparral.
Colloidal Silver (ionic silver, native silver, Silver in suspending agent) Uses: Fungal and other infections, Lyme disease, rosacea, psoriasis, food poisoning, chronic fatigue syndrome, HIV/AIDS. Possible dangers: Bluish skin, mucous membrane discoloration, neurological problems, kidney damage. Comments:Likely unsafe. The FDA advised consumers about the risk of discoloration on Oct. 6, 2009.
Comfrey (blackwort, common comfrey, slippery root) Uses:Cough heavy menstrual periods, chest pain, cancer. Possible dangers: Liver damage, cancer. Comments: Likely unsafe. The FDA advised manufacturers to remove comfrey products from the market in July 2001.
Country Mallow (heartleaf, Sida cordifolia, silky white mallow) Uses: Nasal congestion, allergies, asthma, weight loss, bronchitis. Possible dangers: Heart attack, heart arrhythmia, stroke, death. Comments: Likely unsafe. Possible dangers linked with its ephedrine alkaloids banned by the FDA in 2004.
Germanium (Ge, Ge-132, germanium-132) Uses: Pain, infections, glaucoma, liver problems, arthritis, osteoporosis, heart disease, HIV/AIDS, cancer. Possible dangers: Kidney damage, death. Comments:Likely unsafe. The FDA warned in 1993 that it was linked to serious adverse events.
Kava (awa, Piper methysticum, kava-kava) Uses: Anxiety (possibly effective). Possible dangers: Liver damage. Comments: Possibly unsafe. The FDA issued a warning to consumers in March 2002. Banned in Germany, Canada and Switzerland.
Lobelia (asthma weed, Lobelia inflata, pukeweed, vomit wort) Uses: Coughing, bronchitis, asthma, smoking cessation (possibly ineffective). Possible dangers: Toxicity; overdose can cause fast heartbeat, very low blood pressure, coma, possibly death.Comments: Likely unsafe. The FDA warned in 1993 that it was linked to serious adverse events.
Yohimbe (yohimbine, Corynanthe yohimbi, Corynanthe johimbi) Uses: Aphrodisiac, chest pain, diabetic complications, depression; erectile dysfunction (possibly effective). Possible dangers: Usual doses can cause high blood pressure, rapid heart rate; high doses can cause severe low blood pressure, heart problems, death. Comments: Possibly unsafe for use without medical supervision because it contains a prescription drug, yohimbine. The FDA warned in 1993 that reports of serious adverse events were under investigation.
Source: Natural Medicines Comprehensive Database, Professional Version, June 2010