The subject matter of the present invention is the use of chitin or a derivative of chitin for preventing and/or treating parasitoses, and in particular cryptosporidiosis. The present invention also pertains to a composition that comprises at least one base agent chosen from among chitin or a derivative of chitin and at least one secondary agent chosen from among an agent for stimulating immunity and an antiparasite agent, as well as the use of same for preventing and/or treating parasitoses, in particular cryptosporidiosis.