This study was carried in order to determine short-term (acute) and long-term(subchronic) effects of Melastomastrum capitatum leaf methanol extract in the management and treatment of certain diseases in traditional and complementary medicines  by many villages in Mambila Nigeria. Acute and subchronic toxicities were carried out in  accordance with the Organization for Economic Cooperation and Development (OECD) guidelines.  Acute toxicity test was carried out with a limit test dose of 2000 mg/kg body weight of  leaf extract administered via orally gavages to five wistar albino rats grouped into five groups of one rat each, and observed carefully for signs of toxicity especially for the first 4 h and then once daily for 14 days. Subchronic toxicity was carried out in 30 wistar albino rats of opposite sexes divided into five groups of six  rats . Doses of 250 mg/kg, 500 mg/kg, 1000 mg/kg and 2000 mg/kg body weight of  M. capitatum leaf  extract were administered to the rats for 28 days orally. Blood samples were collected from the rats by cardiac puncturing for hematological analysis, liver function, lipid profiles and serum biochemical analysis. The test limit dose did not cause any mortality or signs of acute intoxication in the rats. There was no significant difference between hematological, liver, lipid and biochemical parameters  in the control rats and treatment groups (p ≤ 0.05) after subchronic study. No  major organs damage was seen. The study showed that M. capitatum leaf extract is safe when administered at the test limit dose orally in treatment of diseases in traditional medicine.