Zn(II)PPIX exerts antitumor effects against C-26 adencarcinomas in mice. BALB/c mice were inoculated with 1 × 105 of C-26 cells. On day 7 after inoculation of tumor cells mice were treated with Zn(II)PPIX administered i.p. or p.o. for 7 consecutive days [A and B]. Graphs show the influence of the treatment on the growth of C-26 tumors in mice. *P < 0.05 (two way Student's t-test) in comparison with controls.