RESUMO
BACKGROUND: The importance of traditional medicine, one of the fundamentals of the cultural heritage of African, Asian and South American peoples, is evident in that such medicine is practised by more than 80% of these populations. METHODS: To analyse the methodology of clinical trials using medicinal plants, we reviewed articles published on this topic between 1980 and 2000. RESULTS: Forty-eight clinical trials were identified. Most were carried out in developed countries. Standard methodological principles were applied in almost all the trials: randomisation (85.4%), comparison (87.5%) versus placebo (95.2%), and blinded design (81.3%). The duration of the studies was short. Sample sizes were generally small, ranging from 30 to 99 subjects; statistical tests were used in 90% of the trials. Adverse effects were infrequently collected. CONCLUSION: Most clinical trials included in this survey were conducted in accordance with WHO guidelines. Respect for methodological principles and the implementation of a legislative framework are important in obtaining credibility and international recognition of the traditional pharmacopoeia.
