Three intraperitoneal injections daily of 1 mg/gm body weight of 20% lactose, glucose-fructose and sucrose in saline, in rats from the 10th to 19th day did not give a definite effect on caries prevalence or extent after 35 post-weaning days on a nutritionally adequate cariogenic ration. There were no effects on weight gain before or after weaning, food consumption or femoral and mandibular weights.