People who ingest even small amounts of these alkaloids for a prolonged time may be at risk for developing cirrhosis of the liver. Comfrey is sold as teas, tablets, capsules, tinctures, medicinal poultices, and lotions. Use of this nonessential element for a long time may cause serious, irreversible kidney damage and has resulted in death. There is no evidence of effectiveness. One brand resulted in hospitalization of at least 10 patients and one death from a blood clot after surgery to remove a throat blockage.
Guar gum can cause diarrhea, vomiting, bloating, and intestinal blockages.
Unapproved labeling claims this Chinese herbal product is useful for relieving pain. After accidentally taking Jin Bu Huan, three preschool children were hospitalized this year in Colorado with life-threatening, very slow heart rates, depressed central nervous systems, and breathing difficulties. After intensive medical care, the children recovered. Products with Ma huang, derived from an evergreen plant, are under investigation following reports to FDA of serious adverse effects such as high blood pressure, rapid heart rate, nerve damage, muscle injury, psychosis, stroke, and memory loss. Ma huang is sold in products for weight control or boosting energy.