The influence of hydrogen sulfide, dithionite, sulfite, thiosulfate, and sulfate anions on human platelet aggregation was investigated in vitro. It was established that sulfite, thiosulfate, and sulfate did not influence the platelet aggregation induced by ADP, collagen, or epinephrine in the concentrations range 10-1000 microM. Hydrogen sulfide and dithionite inhibited platelet aggregation induced by ADF or collagen in a dose-dependent manner. The action of hydrogen sulfide began in concentration of 100 microM and the action of dithionite began in concentration of 1000 microM. They did not influence epinephrine-induced platelet aggregation.