We describe the case of a patient with ulcerative colitis who suffered a pulmonary embolism that caused shock. Despite the high risk of haemorrhagic complications given the underlying disease, thrombolytic treatment was administered with a good result. Deep vein thrombosis in the lower limbs and pulmonary embolism are the most common thromboembolic phenomena in patients with inflammatory bowel disease. The inflammatory and thrombotic processes are connected, creating a vicious circle. Inflammatory bowel disease predisposes to thromboembolic episodes, while thrombosis, if not the initial cause, is at least implicated in maintaining the inflammatory process in ulcerative colitis and Crohn's disease.