Aluminum sulphate has a significant toxic effects for humans. Aluminum is one of the most abundant metal on the Earth crust. The purpose of this study is to evaluate the effects of short term exposure to aluminum sulphate on the bone development of the fetuses in rats, and if folic acid has a protective role upon that effects or not. Forty female rats were used, ten per group, GI served as negative control (receive nothing except normal feeding and water), GII served as positive control (receive water by gastric gavage), GIII treated with aluminum sulphate orally by gastric gavage and GIV treated with aluminum sulphate with folic acid. Mating occurred and known by presence of vaginal plug in the female rats. Rats were killed on day 18 of gestation. Results: The female rats weight were significantly reduced in the treated group if compared with the control group (p > 0.001), all parameters of the fetuses, fetal weight, malformation and the crown rump length reduced significantly p value were <0.000, <0.001, and <0.000 respectively. In histopathological results the aluminum treated group showed severe limited area of preossfication in fetuses vertebrae. Folic acid gave a protective role for all the hazardous effects of aluminum sulphate and prove the diameters measured and also the histopathological effects. Conclusion: Aluminum sulphate can produce hazardous effects on bone of the fetuses, which may affect the life style of these fetuses later on. Folic acid might give a protective role and so should be given to females who tried to conceive.