Theophylline serum levels were studied after oral administration of slow release theophylline (Talofilina®) in children with bronchial asthma. The children received the drug as closed capsules or as granules, obtained by opening the capsules, for 1 week in each form. The mean dose used was 8.6 mg/kg every 12 h. The theophylline blood leves at 4, 8 and 12 h after drug ingestion were significantly lower when granules from open capsules were used. Our recommended dose of Talofilina for Brazilian children is 16 mg/kg/day, if administered as closed capsules, every 12 h. On open capsule administration every 12 h, the total daily recommended dose is 20 mg/kg/day.