Microscopically, the pseudomembrane is seen to be composed of inflammatory cells, necrotic epithelium, and mucus in which the overgrowth of microorganisms takes place. The underlying mucosa shows congested vessels, but is still intact.

Treatment with oral metronidazole is useful in mild to moderate cases. The use of fecal transplantion has markedly reduced morbidity and mortality from multiple recurrent pseudomembranous colitis. The response rate is over 90%, via administration by enema, with no significant side effects.