Acute cholecystitis after colonoscopy is a rare event, with less than 10 cases described in the literature. We report the case of a male patient with silent gallstones who underwent colonoscopy for follow-up of his Crohn's disease. The colonoscopy revealed erosions in the terminal ileum, from which biopsies were taken. A sessile polyp 4 mm in diameter at the recto-sigmoid junction was also removed. Less than 24 h after the colonoscopy, the patient complained of upper right quadrant pain, nausea and vomiting. Based on the clinical findings, laboratory data and ultrasonography, we diagnosed acute cholecystitis and excluded any complication after the colonoscopy. Laparoscopic cholecystectomy was performed and the patient was discharged. LEARNING POINTS• Cholecystitis following colonoscopy can be a rare complication or a coincidence.• Rarely, manoeuvres during colonoscopy may dislodge small gallstones which then obstruct the bile duct causing acute cholecystitis.• Imaging and the clinical picture help to differentiate bowel perforation, a fairly common early event after colonoscopy, from other complications.