The study was made of nitric oxide (NO) generation by leukocytes of peripheral blood from healthy subjects and patients with a compound trauma. How to isolate leukocytes from the whole blood is shown. Leukocyte isolation rate reached 98%. Generation of NO by leukocytes was made in the medium containing medium RPMI 1640 (free of phenol red), calf embryonic serum (5%), L-glutamine (2 mM), gentamycin (80 mcg/ml), penicillin (100 U/ml), streptomycin (100 mcg/ml). Incubation lasted for 15 h at 37 degrees in tissue culture plates with 24 cells 16 mm in diameter (Costor, USA). NO generation was defined in supernatants of cultivated leukocytes (5 x 10(6)) with Griss reagent in reaction with stable metabolite nitrite. NO content among the leukocytes from healthy subjects was 0.63 +/- 0.08 nmol, in trauma 1.10 +/- 0.08 nmol, relative production of NO by healthy subjects was 1.27 +/- 0.17 mumol/l, in trauma 2/21 +/- 0.18 mumol/l, absolute production was 0.99 +/- 0.15 mumol/l and 1.98 +/- 0.19 mumol/l, respectively. The findings point to an important role of nitric oxide generation by leukocytes in reaction with superoxide radical in production of peroxynitrite responsible for severity of endotoxicity.