The bioavailability and absorption pattern of theophylline from Theolong granule and Theodur-G were studied in five healthy volunteers both in fasting conditions and after taking two different meals. In all the subjects, no dose-dumping effect was observed with a standard- or a fat-rich breakfast on these preparations. Postprandial administration delayed the absorption of theophylline and a fat-rich breakfast significantly reduced the area under the curve (AUC0-26) for both preparations. The mean AUC decreased by 14.0% for the former and 19.7% for the latter when the fat-rich breakfast was administered. Intake of a standard breakfast resulted in a decrease in the AUC0-26 by 10.6% for Theolong granules but there was little effect observed with the Theodur-G granules.