Background: One of the main causes of morbidity in hospitalized patients, and especially in the intensive care unit (ICU), is venous thromboembolism (VTE). The best way to deal with VTE is prophylaxis. Rational prophylaxis should be provided after risk factor analysis. Different prophylaxis regimens are pharmacological and physical. Pharmacological prophylaxis regimens consist of heparin and enoxaparin that are given subcutaneously.