Toxicological problems resulting from exposure to traditional remedies and food supplements

The National Poisons Unit, London, carried out a pilot survey to investigate the frequency and severity of adverse effects/toxicity from exposure to traditional medicines and food supplements reported to the Unit. Enquiries related to suspected poisoning events were reviewed retrospectively from January 1983 to March 1989, and prospectively in 1991. Further information about cases identified by the prospective review was obtained, when appropriate, by follow-up questionnaire, clinical consultation by a consultant toxicologist, toxicological analyses of samples from patients and from products, and botanical identification of dried plant material. In total, 5536 enquiries were identified. Symptoms were reported in 657 (12%) of these. There was a large number of reports of accidental ingestion of vitamin preparations by children under 5 years. Appropriate assessment was possible in only relatively few cases, due to insufficient documentation, and poor labelling of certain products. A probable link between exposure and adverse effects was identified in 42 cases, and was highly probable in two. Heavy metal poisoning resulting from use of contaminated traditional remedies was confirmed in 5 cases. There was evidence that some patients took excessive doses of food supplements, without realising that this might result in toxic effects. The results of this pilot study suggest that there is a need for further surveillance to provide an appropriate risk assessment of food supplements and herbal remedies, improved quality control and labelling of these products, and increased awareness of their potential hazard.