Complications in the use of sodium hypochlorite during endodontic treatment. Report of three cases. In endodontic treatment, solutions of sodium hypochlorite are widely used as an irrigating agent. It is an effective solvent of both necrotic and vital tissues, which makes it toxic to the surrounding tissues. Complications are rarely reported. Nevertheless, the acute symptoms caused by the toxic reaction must not be underestimated. Causes, treatment, and prevention of complications of sodium hypochlorite use are discussed, and three case reports are presented. 