Alcide gel is a germicidal agent which is highly effective in killing a wide range of bacteria and fungi in vitro within 1 min. Alcide gel consists of sodium chlorite and lactic acid, parts A and B, respectively. Chlorine dioxide is formed when sodium chlorite and lactic acid, the active ingredients of Alcide, are mixed. The objective of this investigation was to study the teratogenic effects of Alcide gel both in rats and in mice. The gel was administered topically in doses of 1 and 2 g per kg body weight on days 6-15 of gestation. No toxic symptoms were observed following exposure of pregnant rats and mice to Alcide gel. Viability of the fetuses as well as weight, length and number of resorptions were quite similar compared with control groups. Fetuses were examined for external, visceral and skeletal anomalies. Some incidence of missing or incompletely ossified sternebrae, missing ribs and incomplete ossification of skull bones were observed from skeletal examination. Gastromegaly, kidney agenesis, heart displacement, interatrial septal defect, limb hyperflexion and club foot were observed from soft-tissue examination. These defects, however, were not significantly different compared with control animals. Alcide gel was not teratogenic at the doses tested.