Healthy volunteers received intravenous and/or oral doses of sodium dichloroacetate (DCA) in various single and multiple dose regimens. A crossover bioavailability study proved abortive because second and subsequent doses showed significantly longer terminal elimination half-lives (means 3.64 h and 9.9 h, respectively) than was the case for initial doses (1.58 h). A parallel bioavailability comparison failed to show that oral doses were significantly different from 100 per cent bioavailability (AUCoral, 604 micrograms h-1 ml-1; AUCi.v., 489 micrograms h-1 ml-1). The time required to elapse between individual doses, in order to prevent second doses having relatively long half-life values, varied in different individuals from 1 week to greater than 3 months. No cardiac or central nervous system effects were recorded by echocardiography and digit symbol substitution tests, respectively. The mean renal clearance of DCA was 42.9 ml h-1. No differences were observed in DCA kinetics between male and female subjects.