High concentrations of organic solvents have adverse effects on the health of professional workers. In endodontics, halothane, chloroform and xylene are used to dissolve gutta-percha from root canals. It is therefore questioned whether the use of these solvents could affect the health of patients or of the dental team. It seems warranted to conclude that the amounts and concentrations of chloroform, xylene and halothane such as used in endodontic retreatment, are low and therefore are safe. However, the dentist should be aware of possible hypersensitivity induced by previous application of halothane as a narcotic.