Abstract: The Chinese drug,“Ya-tan-tze”,is the fruit of Brucea javanica (L.) Merr..It has been used against malaria and dysentery (amoeba).It consists of glycosides, alkaloid,oil and other substances,which have been studied by several authors. The present paper deals with the chemical composition of its oil.The oil was analyzed and its composition thus found is summarized below: (1)Unsaponifiable matter“Crystalline compound,may be phytopte rol,(m.p.127-128°) Crystalline compound,may be hydrocarbon,(m.p.88-89°) Fatty acid Essential oil a ……1.36% (2)Saponifiable matter:Oleic acid……81.87% α-Linoleic acid……3.37% Palmitic acid……6.62% Stearic acid……2.65% Water soluble fatty acid……1.10% (3)Mother liquid……4.59% Total 101.56%.