In the present paper the effect of the pretreatment with epsilon-amino-trimethyllysine (TML) 10 mg/kg on the DGA-induced hepatitis in mice is described. TML-pretreatment was chosen because experiments indicated that TML treatment elicits processes in the liver similar to that occurring during regeneration on one hand, on the other hand because it was shown that DGA proved to be ineffective in newborn or in partially hepatectomized animals, that is to say on regenerating liver. It was expected that TML pretreatment would protect the animals against the hepatitis inducing effect of DGA. Unexpectedly pretreatment with TML had just the opposite effect, resulting in a severe hemorrhagic hepatitis in several animals. Biochemical and morphological studies are in progress to elucidate the mechanism of this peculiar effect.