Serum and tonsillary tissue levels of cefroxadine, a new broad-spectrum cephalosporin, proving to be effective in several infections, particularly in the ENT ones, were measured in patients scheduled for tonsillectomy. Twenty patients (12 males, 8 females) aged between 11 and 25 years (mean 18.0 years) were given cefroxadine for 2 days (500 mg every 12 h), and on the 3rd day 500 mg of the drug was given before surgical operation. Tonsillar tissues were taken 2 h after dosing and blood samples before, 1, 2, 4 and 6 h after the drug administration in 8 out of 20 enrolled patients. Cefroxadine concentrations were measured according to microbiological methods. Cefroxadine tonsillary levels were 1.13 +/- 1.73 micrograms/g, approaching the MIC for sensitive bacteria. The time course of plasma levels is superimposable to previous studies. These findings suggest a rapid penetration of cefroxadine in tonsillar tissue and seem to confirm the clinical efficacy of the drug in ENT infections.