Oral disinfectants containing chlorhexidine or hexetidine are able to produce disturbances of taste, as demonstrated by Krarup's electrogustometric method and the gustometric method of Harris and Kalmus. Hypo- and dysgeusia are characterized by dissociated disturbances, the most prominent of which concerns the sweet perception. The bitter taste is least affected, whereas the effects on salty and acidic tastes range between that for sweet and bitter. Taste disturbances which include ageusia for 48 h were observed when the tongue was touched with a 20% solution of chlorhexidine. Not only the disinfectants themselves provoked dysgeusia but also other "taste improving" agents (particularly, the volatile oild). In addition to dysgeusia, the authors found disturbances of the mucous membrane sensitivity caused by the test substances.