Eight young adult male volunteers with a basic (alimentary) plasma boric acid concentration of less than 0.10 - 0.46 mg/l were given a single dose of boric acid (562-611 mg) by 20 min IV infusion. The plasma concentration curves, followed for 3 days, best fitted a three-compartment open model, although two subjects had to be left out due to inconstant basal plasma concentration values or failure to fit to the three-compartment model. The 120 h urinary excretion was 98.7 +/- 9.1% of dose, Cltot 54.6 +/- 8.0 ml/min/1.73 m2, t1/2 beta 21.0 +/- 4.9 h and distribution volumes V1, V2, and V3: 0.251 +/- 0.099, 0.456 +/- 0.067 and 0.340 +/- 0.128 l/kg.