The effect of allylisothiocyanate, the major compound of radish on the growth of Aspergillus parasiticus R-716 and aflatoxin production, was investigated. An increase in the level of allylisothiocyanate results in a decrease both growth and aflatoxin per myclial weight, and the addition of 125 ppm allylisothiocynate completely inhibited the growth of this strain. The addition of allylisothiocyanate to the culture of R-716 strain delayed the production of atlatoxin. The inhibition of aflatoxin was more B-group than G-group and M-group during cultural period. The growth of strain and aflatoxin production were greatly affected by the addition of allylisothiocyanate.