The effects of drugs with different mechanisms of action on the human gallbladder smooth muscle are reviewed. Sincalide, the C-terminal octapeptide fragment of cholecystokinin, caused a clinically important contraction of the gallbladder during oral cholecystography in 72% of the patients. Within 8-12 min cystic duct visualization occurred in 44% and common bile duct visualization, in 17%. On the other hand, the standard concentration meal (200 ml cream) caused a more reliable gallbladder contraction in 30 min. One tablet of Baralgin, i.v. proxyphylline (300 mg), and i.v. glycopyrrolate (0.2 mg) had no relaxing effect on the contracted gallbladder during oral cholecystography. Similarly, i.v. metoclopramide (20 mg) and i.v. prostaglandin E2 (25, 50, and 75 micrograms) were ineffective, whereas 1 ampule of Baralgin and 1 ampule of Palerol i.v. caused a significant dilatation. Litalgin i.v. 1 ampule, i.v. papaverine (40 mg), and sublingual nitroglycerin (0.5 mg) had a slight relaxing effect on the smooth muscle of the gallbladder. In an acute attack of pain in a patient with gallstones, i.v. administered Baralgin and Palerol seem to be effective; i.v. Litalgin, i.v. papaverine, and sublingual nitroglycerin may be of value in milder biliary tract disorders, but the benefit of i.v. proxyphylline, i.v. glycopyrrolate, and oral Baralgin is questionable. Metoclopramide can be used as an antiemetic drug in patients with gallstones.