The aim of study is to analyze the biochemical and histopathological changes of oral administration of various formulations of Morinda tinctoria leaves on alloxan induced diabetic rats. Ethanol and Ethyl acetate extracts of leaves of M.tinctoria. on serum glucose, haemoglobin, glycosylated haemoglobin (HbA1c), plasma insulin, C-peptide and urea levels were assessed and the histological changes in the liver, pancreas and kidney tissues of control and experimental groups were examined. Oral administration of ethanol and ethyl acetate extracts of Mt. for 35 days significantly reduced the levels of serum glucose, HbA1c and urea while it increases the levels of plasma insulin, haemoglobin and C-peptides. Supplementation of ethyl acetate extract of M.tinctoria extract improves histopathological alterations in the liver, pancreas and kidney. Therefore, it could be used as a natural source for prevention or early treatment of diabetes mellitus.