Abstract: The aim of the present study to evaluate the activity of seselin on A. flavus. Seselin, a coumarin, was isolated from hexane extracts of aerial parts of Decatropis bicolor. Seselin exhibited fungistatic activity against Aspergillus flavus at a concentration of 31.25 μg mL-1. When tested on stored maize var. Cacahuazintle, it was found that seselin, at 1.0 and 2.0 mg of seselin/100 g of grain, offered the same degree of protection against A. flavus as that offered by daconil (100 mg) or propionic acid (0.2 mg).