The variety of pathological changes that occur during parasitic infections is diverse. Recently there has been done considerable progress in understanding the physiopathologic aspects of the direct parasitic action of the products that they release, that affect the digestive function. The pathogenetic effects of intestinal parasites are important, not only for the adult forms that occupy the lumen or the intestinal mucosa, but for the migratory forms. The most important clinical manifestations are in direct relation with the host response to the aggression or trauma caused by the migratory larvae and/or adults parasites, the signs and symptoms depends on the infestation phase and on the severity or in the agent "virulence". The objective of this article is to present a brief revision on the physiopathologic effects of infestations by intestinal parasites.