['In the present report, we analyze the efficacy of the sanitary regulations to kill the Anisakis simplex larvae (As L3) (heat or freeze) to avoid the gastrointestinal alterations that it provokes. We studied the effects on intestinal contractility (muscular tone, amplitude, and frequency of the twitches and cholinergic and alpha-adrenergic stimulus) of As L3, their crude extracts (CE) and excretory-secretory products (ESP), untreated or heated (60 degrees C for 15 min) or frozen (-20 degrees C for 24 h) using rat ileum and an isometric system. Carbachol and noradrenaline have been used as cholinergic and alpha-adrenergic stimulus, respectively. We determined that viable As L3, their untreated CE and ESP, as well as all their frozen counterparts, altered the intestinal contractile activity and its autonomic control. In contrast, heated As L3, CE, and ESP were incapable of provoking any change in rat ileum motility, suggesting an inhibitory effect by the heating procedure.'] Does freezing infective-stage larvae from Anisakis simplex and their produce at -20 degrees C for 24 h prevent the occurrence of autonomic imbalance in rat ileum?