The effect of cis-diamminedichloroplatinum (DDP) on small intestinal absorption of saccharides, and the protective effect of N-p-hydroxymethylbenzyl-D-glucamine dithiocarbamate (HBGD) on DDP-induced intestinal toxicity were studied. The small intestinal absorption of d-glucose and d-galactose, which are actively absorbed, decreased 2 days after DDP administration. The activity of Na + ,K + -ATPase in the intestinal tissue was not inhibited by DDP administration. The small intestinal absorption of maltose and sucrose decreased 2 and 4 days after DDP administration. The activities of maltase and sucrase in the intestinal mucosa decreased after DDP administration, but these enzyme activities in control mice were not inhibited by DDP in the in vitro experiments. A scanning electron micrograph of the jejunum after DDP showed damage in the villi. These results indicate that the inhibitory effect of DDP on the small intestinal absorption of saccharides results from the DDP-induced mucosal damage. Treatment with HBGD (1 mmol/kg) 5 min after DDP injection prevented the decreases in the intestinal absorption of d-glucose,d -galactose, maltose, and sucrose. Platinum (Pt) concentrations in the small intestine after DDP administration decreased following HBGD treatment. Biliary and urinary excretions of Pt after DDP administration were remarkably increased by HBGD treatment. These results indicate that the administration of DDP to mice causes the decrease in the intestinal absorption of saccharides, and that HBGD can effectively remove Pt from the intestine through biliary and urinary excretions, resulting in protection against the intestinal toxicity induced by DDP.