In order to evaluate the influence of food and time of administration on the absorption of diethylamine chromocarbe, a bioavailability study was performed in 8 volunteers by using a new method of plasmatic drug evaluation. The results obtained indicate that lunch has little effect on diethylamine chromocarbe absorption in comparison with the administration 0.5 h before breakfast. The bioavailability parameters Cmax, tmax, and AUC are not statistically different and the two methods of administration can be considered as bioequivalent. The absorption of diethylamine chromocarbe seems to be reduced when the drug is administered before dinner. This delay on absorption may be due to circadian rhythm of tractus gastrointestinal absorption or to the reduction of physiological activity of volunteers.