Envenomation from bite of exotic snakes is rare in France and represent a serious therapeutic problem: only an adapted antivenom is effective and obtaining such a treatment is a real difficulty. The authors report two clinical cases of envenomation with defibrination after bite by pit vipers from South America. The two patients were treated with nonspecific antivenom therapy with divergent results. The use of the paraspecific effects of antivenom can allow an effective treatment in the absence of specific antivenom, but requires to be known better.