Modern surgical procedures become very extensive and aggressive in every surgical branch. Due to expressive development of anesthesia techniques with large monitoring systems support is provided to patients for broad spectrum of disorders. Therefore, we need to protect patients from imminent complications, as development of deep venous thrombosis and embolic pulmonary incidents. The main target in prophylaxis is to divide patients by risk and the type of surgical procedures during the time of "bed recovery". Today, current farmacological treatment is prone to control and prevent such events and to decrease mortality. Patients are divided in three groups: low risk (small operations with early mobilization); medium risk (surgery with risk in patients history); high risk (severe patients and long surgery, prolonged recovery). The best solutions in current medicine is to prevent most of complications, by administration of low molecular heparin (LMWH). Advantages of that treatment are: no need of intensive monitoring, long-time treatment, safe usage in "day case surgery" Beside LMWH, we still use heparin, although we tend to trial newer treatments and supports for prevention of complications. For special groups of patients recent trials examine heparinoid like drug-hyrudin, provided by chemical engeneering. That drug is metabolised in liver. Current therapy and prevention of DVT and pulmonary embolia is LMWH. It entered in every alghorythm of surgical and anaesthetic procedures and become CONDITIO SINE QUA NON.