Twelve mongrel dogs had superficial and deep colon biopsies above and below the peritoneal reflection. Six of the animals were given a barium enema; two had a barium enema immediately, two in three days, and two in six days. The animals were sacrificed 48 hours after the barium enema; the sigmoid was removed and tissue was examined macroscopically and microscopically. When healing rates of the biopsy sites were compared with those of control animals, there was no difference. The results suggest that barium has no deleterious effect on the healing of superficial or deep colorectal biopsies.