Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by recurrent episodes of inflammation and ulceration in the colon. Patients with UC are at an increased risk for thromboembolic events, including pulmonary thromboembolism and venous thrombosis, as extraintestinal complications. However, cerebral thrombosis is uncommon in these patients. We report a rare case of cerebral hemorrhagic venous infarction in a patient with severe UC who was receiving prophylactic heparin therapy. CT scans revealed a hypodense lesion with hyperdense hemorrhagic foci in the lobulated, contoured left parieto-occipital area, confirming the diagnosis of cerebral hemorrhagic venous infarction. Despite negative results from additional thrombotic and immunological tests, the patient passed away 10 days later from multi-organ dysfunction syndrome secondary to brain injury. This case underscores the critical need to consider cerebral hemorrhagic venous infarction, even in patients with severe UC who are on prophylactic heparin, particularly when presenting with headaches and visual disturbances.