The toxic and teratogenic effect of AlCl_3 on leghorn chick embryos were studied. Different concentrations of AlCl_3 dissolved in redistilled water were injected into the air sac of the eggs (0.2 ml per egg) on the third day of incubation. It was identified that the maximal permissible dosage was 1.708 ?mol/egg, the minimal lethal dosage was 2.25 ?mol/egg, the absolute lethal dose was 35.34 ?mol/egg, and LD_(50) was 8.09 ?mol/egg. The mortality of the embryos raised with the increase of the dose of AlCl_3. AlCl_3 also retarded the development of chick embryos and showed apparent tetratogenic effects.