Embryopathic effects of ethanol and caffeine in the chick.

The combined effects of ethanol (20 and 40%, 0.1 ml/egg) and caffeine (0.5 and 1 mg/egg) on early chick embryos were investigated. After treatment with 0.5 mg caffeine and 20% ethanol at 48 h incubation, teratogenicity was potentiated, but without affecting embryonic growth. Embryotoxic interactions of this nature might account for congenital defects of doubtful etiology.