The tolerability of the compound AWD 26-06 (which is to classify as a M1-antagonist in consequence of the pharmacological investigations) was investigated in 11 healthy male persons with increasing dosage from 5 to 150 mg. Dryness of the mouth and scratch in the throat were observed by a dosage of 50 mg onwards, a diminuation of the flow of saliva and the accommodation were observed by a dosage of 100 and 150 mg, respectively. The frequency of the heart, but not the blood pressure, is increased by 150 mg of AWD 26-06. The influence on the secretion of the gastric juice was investigated in normal conditions and after stimulation by Pentagastrin with a dosage of AWD 26-06 of 25 mg in comparison with a placebo on 7 healthy male persons. The volume of gastric juice was diminished by 35% in all fractions, but the secretion of HCl, measured as basal acid output and peak acid output, was diminished in 5 of the 7 persons by 20%. A further investigation in order to check the therapeutic effect in patients with ulcus ventriculi and ulcus duodeni, respectively, is necessary and useful.