The present experimental study was conducted to evaluate the effect of methanolic extract of stem bark of Neolamarckia cadamba against streptozotocin-induced diabetes in wistar rats. The % extractability and qualitative phytochemical analysis of the Neolamarckia cadamba methanolic extract of stem bark were conducted while studying its anti-diabetic potential. The phytochemical analysis revealed the existence of active constituents, it was found that the presence of flavonoids, alkaloids, proteins, amino acids, carbohydrates, saponins, phytosterols, resins, tannins, glycosides, and phenolic compounds and the extractability percentage was obtained to be 13.40%. GC-MS analysis report revealed the presence of a total 31 bioactive compounds. hexadecanoic acid ethyl ester, octadecanoic acid ethyl ester, n-hexadecanoic, pentadecanoic acid, ?-Sitosterol, and ?-Sitosterol acid are pharmacologically important phytoconstituents in Neolamarckia cadamba extract. The serum biochemical, haematological and histopathological changes in the pancreas, liver, and kidney were among the parameters used to evaluate the anti-diabetic effects of the methanolic extract of Neolamarckia cadamba stem bark.