The authors studied serum theophylline levels after administration of new single-dose capsules: Teonova. Special attention was paid to possible fluctuations of serum theophylline after administration of the drug following a standardized meal. For this purpose a test was carried out on eight male patients with intrinsic asthma. The patients were given a dose able to produce a serum concentration of theophylline of between 10 mcg and 20 mcg at the tenth hour after the administration. This dose was found to be 400 mg (2 tablets of 200 mg) for one patient and 600 mg (2 tablets of 300 mg) for the remaining seven. The capsules of Teonova were administered to each patient for two subsequent days at 07h00. On the first day the patients had their capsules after fasting, and on the second day after a standardized meal. The test proved that Teonova assured a satisfactory serum theophylline level throughout the 24 hours in all patients; food in no way affected the absorption kinetics of the drug. Such features make Teonova suitable for long-term theophylline therapy.