Long-term and low dose oral malathion exposure causes morphophysiological changes in the colon of rats

•Long-term and low dose oral malathion (LTLD-MAL) exposure can be toxic to the colon.•LTLD-MAL provoked an increase in defecation of less dehydrated feces in rats.•There was a generalized atrophy in the layers of the colonic wall.•There was loss of general and nitrergic myenteric neurons and atrophy of submucosal neurons.•There was increased frequency, duration and direction of colonic migratory motor complexes.