We compared the plasma paracetamol levels attained after the administration of different doses of rectal paracetamol in healthy children to see if they attained therapeutic levels (> 10 microg x ml(-1)). We recruited 24 children (ASA I-III) over 25 kg undergoing elective surgery. They were randomly assigned to receive rectal paracetamol at a dose of 1 g or 40 mg x kg(-1). Blood samples were taken for analysis at 2, 3, 4 and 5 h post dose. Most children in the 1 g group failed to attain therapeutic plasma levels, whereas those in the 40 mg kg(-1) group did achieve therapeutic levels (mean maximum concentration = 7.8 vs. 15.9 microg x ml(-1), p = 0.009).