摘要Objective: To explore the phytochemical constituents present in Allamanda cathartica (A. cathartica) L. using GC-MS. Methods: 20 g of the powdered leaf and stem sample of A. cathartica was equilibrated with 200 d/m of A. cathartica ethanol for 24 h, separately. The volume of the supernatant was later reduced by heating to 2 d/m. The concentrated ethanolic extracts were further subjected to GC-MS analysis. Results: The GC-MS analyses determined the presence of 28 different phytochemical compounds in the ethanolic leaf extract of A. cathartica. The major phytoconstituents were 9,12,15-octadecatrienoic acid (Z,Z,Z)- (16.39%), n-hexadecanoic acid (14.08%), 3-O-methyl-d-glucose (11.03%) and 9,12,15-octadecatrienoic acid ethyl ester (Z,Z,Z)-(10.58%). The ethanolic stem extract of A. cathartica showed the presence of 26 different bioactive compounds. The major ones are 3-O-methyl-d-glucose (29.86%), 2-furancarboxaldehyde 5-(hydroxymethyl)- (14.87%), n-hexadecanoic acid (9.13%) and 9,12,15-octadecatrienoic acid (Z,Z,Z)- (7.34%). Conclusions: This study helps to predict the formula and structure of biomolecules which can be used as drugs and further investigation may lead to the development of drug formulation.