Acetaminophen, a popular nonprescription analgpsic"-;;;6;;"'il d*g' **, 1d'linistered oralllt to pregnant "ts 't a dose levels of o(contro]t): ii, 50, 100, 2oo and 400 mg/kg body,*"igi,la"y on day'1 to 15 of gestation' ir,J lOurt were sacrttted on the day 27 of ;;;gr"*y, and. the fetuses were removed by "r"r.rr.],i',ection and examined body weight showed Lvid"n"" of maternal toxicity as exhibited by marked increase in liver weight and decreasid boJt weight gain' No. increase in the incidence of resorptions was observed even at +oo rngifcg body weight, . a .dose severali- opt.d"c htiiJgeh-e(ti'O if-,z"on thor" uied in human clinical mg/ks body weight)' . There rvas "'lo;;-t;lated' d'""t"*" in fetal body weights rvhich was statistically significant at 2Oo mg/kt weight or more' Examination of the r"tu.E, reiealed insignificant increase in the incia"nce of gross, ikeletal and internal matformations at Jny dose in comparison with the controls. However, one of the fetuses in the gtoup which received 400 mg/kg body ;;ighl shtwed short tail and club foot' Thus' no evrdlnce of embryocidal and teratogenic ef f ects was observed with this analgesicantipyretic drug at the recommended therap" uiit dose in iats. Acetaminophen should be tonsidered the safest analgesic-antipyretic drug during Pregnancy.