Inflammatory bowel disease and paroxysmal nocturnal hemoglobinuria (PNH) are both well-known prothrombotic states. However, ongoing thromboprophylaxis is usually effective in such conditions. However, we report about an imbalance that was triggered by like SARS-CoV-2 infection. There is evidence that SARS-CoV-2 infection leads to thrombosis of vessels. The thrombosis of mesenteric vessels can be multifocal and without respiratory symptoms and leads to devastating consequences like resection of large segments of the bowel and lifelong requirement of parenteral nutritional support. We report about a case of ulcerative colitis (in remission) and PNH where COVID-19 resulted in mesenteric ischemia.