Although systemic hyperfibrino(geno)lysis during hypotensive crisis is known, there do not seem to be recent reports of episodes of primary acute fibrinogenolysis during anaphylactic shock. We report the case of a 61-year-old male admitted to the hospital for anaphylactic shock due to an insect bite who presented a clinical and laboratory picture of severe acute generalized hyperfibrinogenolysis not secondary to disseminated intravascular coagulation (DIC). Without specific therapy, the clinical picture resolved itself spontaneously within 40 hours of onset. Careful clinical examination and the execution of simple laboratory tests permitted a rapid diagnosis and therapeutic success.