RESUMO
BACKGROUND: Fagara zanthoxyloides is a well known medicinal plant in Uganda. It is used extensively in malaria and other infections. However nothing is known about its toxicity. OBJECTIVE: The objective of the study was to evaluate the acute toxicity of the methanolic extract of the root-bark of F. zanthoxyloides, in mice. METHODS: Methanolic extract of the root-bark of the plant was administered orally to mice at various dose levels to determine the acute toxic effects and the median lethal dose (LD50) in mice. RESULTS: The LD50 of the methanolic extract was found to be 5.0 g/Kg body weight within 95% confidence limits. The mice showed signs of cerebral irritation before dying. Histopathological examinations of the viscera showed congestion and focal necrosis of the liver and renal tubules. CONCLUSION: It was concluded that the extract of F. zanthoxyloides is safe, however the cerebral mechanism that lead to the death of the mice need to be investigated further.