This paper reviews progress in establishing the scientific rationale for and safety of traditional medicine use in Africa. Selected plants were screened for antibacterial, antifungal, anthelmintic, anti-amoebic, antischistosomal, antimalarial, anti-inflammatory and antioxidant activity, as well as psychotropic and neurotropic activity using appropriate in vitro tests. Isolation of active compounds, in almost all cases, provided scientific validation for the use of the plants in traditional medicine. Although plants used medicinally are widely assumed to be safe, many are potentially toxic. Where poisoning from traditional medicines has been reported, it is usually because the plants used have been misidentified in the form in which they are sold, or incorrectly prepared and administered by inadequately trained personnel. The issue of quality control may, in the interim, be addressed using chromatographic techniques.