neurons were strongly reduced all over the digestive tract; megacolon appeared only when there was a reduction of over 80% of the number of neurons these pathologies appeared as a result of the disruption of the neurally integrated control of peristalsis (muscular annular contraction) in those parts where a strong force is necessary to impel the luminal bolus of feces idiopathic megacolon and Chagas megacolon appear to have the same cause, namely the degeneration of the myenteric plexus.