Anti-tumoral effects of the Brassica oleracea var. Capitata extract were investigated on the acitis and solid Ehrlich ascidis tumor cells (EAT) which was transplanted to Mus musculus Balb/c mice. It had no significant toxicity. Only 2 of the 15 ascites EAT bearing mice died within 12-14 days but all of the controls died within 7 days. In these mice, peritoneal fluid contained 3 x 10(3) cells/ml and 5 atypical mitosis (magnification x 10) whereas controls had 3 x 10(5) cells/ml and 18 mitosis. Of the 27 solid EAT bearing mice, complete response occurred in 7, partial response in 11 and progression in 9. This extract also prevented the ascites tumor transplantation in 72% of the animals.