Neem seed (Azadirachta indica) was used to study the chemical composition, physicochemical characteristics and fatty acids composition of neem oil, amino acids composition of neem meal, effect of different treatments on the removal of antinutritional factors from neem meal, determination of neem protein subunits molecular weight by using SDS-PAGE and digestability index of neem protein. Neem leaves were also used to investigate the protective effect of neem leaves (ethanol extracts) against the injury of alloxan on; blood suger levels, liver, kidney functions and lipid profile in rats. Results showed that oil was the major component of seed (46.4%) followed by protein (19.44%) and carbohydrate (17.16%).