A new, highly concentrated, fluid paracetamol preparation (paracetamol fluid) was tested on 26 small children and school children. The children were divided into 3 groups on the basis of dosage (5, 10 and 20 mg/kg body weight). The paracetamol serum concentration was determined and the temperature reactions noted. The resorption was rapid; maximum serum level was usually reached after 30 minutes. In most cases, maximum drop in temperature, however, occurred in 3-4 hours. The most obvious and longest lasting drop in temperature was achieved fol following 20 mg/kg body weight dose of the paracetamol preparation. Doses of 5 mg/kg body weight had no significant affect on elevated body temperatures. The most favorable dosage then is between 10-20 mg/kg body weight. The paracetamol concentration in the children under study never exceeded that of 20 mug/ml, even with the higher doses (20 mg/kg). This is far below the toxic threshold of 120 mug/ml. Even higher paracetamol doses of 40 mg/kg body weight, such as may be acciddentally administered, only resulted in a maximum serum level of 50 mug/ml and, therefore, were far below the toxic threshold.