We describe two patients who had a typical levamisole-induced agranulocytosis and a severe infection; the view of other cases found in the literature shows a fundamental fact: the complication can occur after a variable time of prescription (from thirteen days to eleven months), continuous or intermittent. The accidents are imprevisible, and circonspection must be used, not for its antihelminthic properties, but for its prolonged use for immunological purposes, even if some authors have not observed any cases of agranulocytosis in large series. Naturally, the purpose is quite different in the case of a severe rheumatoid arthritis or inesthetic warts, and our two observations are very demonstrative. Mechanism of agranulocytosis has not been totaly clarified: we have observed biological stigmates of immunological process against levamisole (responsible of agranulocytosis?), but essentially medullary lesions (successive regenerative aspects and necrosis) as has been described with pyramidon, and this could explain why the other blood cells are affected in an apparently isolated agranulocytosis.