Halphabarol, the active principle of Proximol, is the most potent of the four antispasmodics present in the national desert weed Cymbopogon proximus or ''Halfa Bar''. Halphabarol is of great value for the management of renal colic and in the expulsion of ureteric calculi as it causes dilation of the ureter below the site of calculus while active propulsion is maintained. Evaluation the congenital malformation of proximol in pregnant albino rats during gestation period. The virgin female rats were mated with male rats and the pregnant rats were orally administered a human equivalent dose (0.05 mg/kg) of Proximol from 5th-20th gestation day. At day 20 of pregnancy, all rats were anesthetized to obtained maternal and fetal data. The treatment group displayed some disorders, which can be summarized as growth retardation, external anomalies, embryonic resorption, and skeletal malformation. We concluded that the oral administration of Proximol resulted in embryonic abnormalities and skeletal malformations.
KEY WORDS: Cymbopogon proximus; Halfa Bar; Malformation.