Carvacrol was evaluated at 10 to 500 ppm as inhibitor of growth and aflatoxin production by two toxigenic moulds, Aspergillus flavus and Aspergillus parasiticus, in a liquid culture medium during 20 and 30 day-incubations at 28-degrees-C and 15-degrees-C respectively. At 28-degrees-C, 500 ppm carvacrol completely inhibited the growth and toxin production by both strains. Carvacrol at 50 and 100 ppm also showed a partial or marked inhibition, especially on toxin production. Increased inhibition was obtained by carvacrol at 15-degrees-C for both strains. Aflatoxin production was inhibited to a higher degree than that for the growth. A. flavus was more sensitive to carvacrol than the A. parasiticus.