Carteolol was orally administered to mice once a day at doses of 3, 30 and 150 mg/kg/day during the perinatal and lactation periods and evaluated on its adverse effects on pregnant animals and their offspring. No appreciably abnormal findings related to the drug administration were revealed. Therefore, it was concluded that carteolol have no serious toxic potential on parturition and lactation by mother animals, no adverse effects on growth and development, and behavioral and reproductive performance of offspring and no carcinogenic action through placental and milk transfer.