Platelet nitric oxide production has been investigated in patients with thoracic and abdominal wounds, thermal trauma, varicose disease, methanol and leponex poisoning. There is correlation between absolute platelets nitric oxide production and fibrinogen plasma level in these patients. The maximal absolute platelets nitric oxide production has been revealed at surgical diseases, and minimal has been observed at methanol poisoning. Irrespectively to etiology and danger of disease, reliable correlation between absolute platelets nitric oxide production and fibrinogen plasma level of these patients is established. Consequently platelets nitric oxide production may be important for haemostatic processes.