In the presented clinical observations, in one patient, acute massive pulmonary embolism developed on the 2nd day after the extended surgical intervention in the colon; in the second case, it developed on the 18th day after the extensive surgical aid against pancreatic necrosis. Clinical predictors of a high risk of death of thromboembolism and the technical impossibility of using another treatment method were the basis for systemic administration of tissue plasminogen activator. The direct result of systemic thrombolysis was the clinical recovery of patients. The hemorrhagic complication diagnosed in one of the observations was in the form of moderate bleeding from a vessel of the gastroenteroanastomosis region. Bleeding was stopped with the minimally invasive endoscopic clipping.