Adult male rabbits, wearing a plastic collar to prevent coprophagy, excreted soft faeces during the first half of the light phase, starting at about the time the light switched on at 0600. While soft faeces were being excreted, food intake was reduced considerably in collared as well as in non-collared animals. Rate of passage of gastrointestinal contents in the rabbit was extremely high. Chromic oxide appeared in the faeces 4-5 h after it had been ingested in pelleted food. Coprophagy had no effect upon the rate of passage of gastrointestinal contents, and chromic oxide passed through at the same rate, whether it was incorporated in soft faeces or in pelleted diet.