The systemic increase in inflammatory mediator levels can induce diverse pathological disorders, including potentially thrombus formation, which may be lethal. Among the clinical conditions in which the formation of thrombi dictates the patient’s prognosis, envenomation byBothrops lanceolatusshould be emphasized, as it can evolve to stroke, myocardial infarction and pulmonary embolism. Despite their life-threatening potential, the immunopathological events and toxins involved in these reactions remain poorly explored. Therefore, in the present study, we examined the immunopathological events triggered by a PLA2purified fromB. lanceolatusvenom, using an ex vivo human blood model of inflammation. Our results showed that the purified PLA2from the venom ofB. lanceolatusdamages human erythrocytes in a dose dependent way. The cell injury was associated with a decrease in the levels of CD55 and CD59 complement regulators on the cell surface. Moreover, the generation of anaphylatoxins (C3a and C5a) and the soluble terminal complement complex (sTCC) indicates that human blood exposure to the toxin activates the complement system. Increased production of TNF-α, CXCL8, CCL2 and CCL5 followed complement activation. The venom PLA2also triggered the generation of lipid mediators, as evidenced by the detected high levels of LTB4, PGE2and TXB2. The scenario here observed of red blood cell damage, dysfunctions of the complement regulatory proteins, accompanied by an inflammatory mediator storm, suggests thatB. lanceolatusvenom PLA2contributes to the thrombotic disorders present in the envenomed individuals.