A series of 745 consecutive cases of endotracheal anesthesia were collected at the National Taiwan University Hospital. Evaluation of the oral conditions was performed before, during and after the anesthesia. Injuries to oral structures were recorded. An 18% incidence of oral injuries was noted and the frequency for dental damage was 12.1%. Maxillary incisors, especially the left ones, were accident-prone. Risk factors identified in this study included large decay or restoration, advanced periodontitis, presence of dental prosthesis, shedding deciduous tooth, class II jaw relationship and anterior crowding. More than one third of the complications occurred during the maintenance or emergence stage of the anesthesia. Recommendations for prevention and management of this problem were given.