Single doses of ampicillin (oral and t.v.), cefotaxime (i.m. and i.v.) and clindamycin (oral and i.v.) were administered to rabbits for the determination of the concentrations of the drugs in the plasma and oral and paraoral tissues. The highest concentration of the drugs was found in the sublingual gland (for ampicillin and cefotaxime) and maxillary bone (for clindamycin) following their oral, i.m. and oral administration, respectively and in sublingual gland following 1.v. injection of the three antibiotics tested. The mean peak concentraions in tissues and plasma was at about 2 hours, following administration of ampicillin, cefotaxime and clindamycin. The overall distributions in oral and paraaral tissues of the 3 antibiotics were as follows: Clindamycin > cefotaxime > ampicillin.