Mycotoxins, which induce mitochondrial swelling, were compared with regard to the swelling patterns. Mycotoxins were tentatively classified into three groups type I, II, and III. The type I mycotoxins induced the swelling which went on to the final stage, the complete disruption of mitochondria, and the swelling velocity proportionally increased corresponding to the increase of mycotoxin concentrations. The type II mycotoxins showed a very swift swelling which turned very soon into a slow swelling. The swelling magnitude in stead of swelling velocity increased corresponding to the increase of mycotoxin concentrations. The type III mycotoxins showed a brief lag time before the initiation of swelling. A few mycotoxins such as emodin, luteoskynn, rubroskyrin, secalonic acid and versicolorins, which are uncouplers of oxidative phosphorylation, did not induce mitochondrial swelling.