Although chlorhexidine has been widely used in the prevention and treatment of gingivitis, its effects on taste sensation have not been well studied. The purpose of the present study was to evaluate taste alterations following regular applications of 0.2% chlorhexidine mouthrinses. 24 healthy and non-smoking clinical instructors, dental assistants and dental students were divided into 3 groups after having reached a status of clinical gingival health by 4 weeks of supervised oral hygiene procedures. Following this, they were asked to abolish all mechanical oral hygiene for a period of 14 days, during which time they rinsed twice daily with different mouthrinses. Group A rinsed with a 0.2% chlorhexidine solution, group B served as control and utilized a 0.001 molar solution of quinine hydrochloride as a placebo rinse. A second control group (C) rinsed with distilled water. At days -3 and -2, as well as at days 1, 2, 13 and 14 of the experimental period, and 1 and 2 days after cessation of the rinsing, taste sensitivity was evaluated by a magnitude estimation, suprathreshold scaling procedure for the 4 taste qualities--sweet, salty, sour and bitter. 6 different concentrations of each of sucrose, sodium chloride, citric acid and quinine hydrochloride were utilized. Magnitude estimations of the perceived intensities of each series of test solutions were calculated. The analysis of co-variance revealed significant differences at the short-term and treatment-related suprathreshold scaling responses between both control groups (B, C) and the test group (A) for the sodium chloride magnitude estimation function. However, no significant inter-group differences in the magnitude estimation function were found for the remaining taste qualities.(ABSTRACT TRUNCATED AT 250 WORDS)