The antipyretic activity of ibuprofen in the Sparklets form was compared, in an equivalence study, with that of paracetamol in the same formulation. The study was conducted as a double-blind multicenter trial, with random allocation of the treatments. One hundred sixteen children of both sexes, aged 4.1 +/- 2.6 years, with a fever related to an infectious disease and a mean temperature of 39 degrees +/- 0.5 degrees C at the time of inclusion, were treated with single doses of either 10.3 +/- 1.9 mg/kg of ibuprofen or 9.8 +/- 1.9 mg/kg of paracetamol. The subjects' rectal temperature was regularly monitored for 6 hours. The statistical analysis of the results confirmed that ibuprofen and paracetamol are equivalent with respect to the following criteria (1) time elapsed between dosing and the lowest temperature: 3.61 +/- 1.34 hours for ibuprofen and 3.65 +/- 1.47 hours for paracetamol (95% confidence interval [CI] of the difference: -0.48; +0.56); (2) extent of the temperature decrease: 1.65 degrees C +/- 0.80 degrees C for ibuprofen and 1.50 degrees C +/- 0.61 degrees C for paracetamol, (95% CI of the difference: -0.41; +0.11); (3) rate of temperature decrease: 0.52 +/- 0.32 degrees C/hr for ibuprofen and 0.51 degrees C +/- 0.38 degrees C/hr for paracetamol (95% CI of the difference: -0.45; +0.55); (4) duration of temperature below 38.5 degrees C: 3.79 +/- 1.33 hours for ibuprofen and 3.84 +/- 1.22 hours for paracetamol (95% CI of the difference: -0.14; +0.12).