Prostaglandins GE2 produces on the gallbladder a rise in intraluminal pressure, an increase in in intraluminal secretion, improves gallbladder contraction and decreases its absorption capacity. In this study, patients who received indomethacin twice a day by rectum, showed a significant reduction in volume and area of gallbladder after 24 and 48 hours (P < 0.05). The gallbladder volume after 24 hours had SEM 9.13 cm3, 95% CI 55.28 + 73.49 (P < 0.05). Score pain reduction after 24 hours was also significant (P < 0.001). The patients who underwent the classical Baralcina treatment of one IV vial BID showed a reduction in diameter and area of gallbladder but this was not statistically significant (P < 0.10). Reduction of volume at 24 hours was SEM 5.34 cm3 95% CI - 64.72 + 76.60 P 0.10 NS; and at 48 hours SEM 3.5 cm3, 95% CI 59.52% + 66.52 P 0.40. Score pain reduction was only significant at 48 hours P 0.001. The number of patients without pain at 24 hours was significantly higher in the indomethacin group ESP 0.21; 95% CI 0.46 + 0.88 P 0.001. In conclusion indomethacin is a useful medication in the treatment of acute cholecystitis and biliary colic due to its anti-prostaglandin effect on the gallbladder.