Amebic dysentery involves inflammation of the intestine (Amebic colitis) with ulcers in the colon due to infection with an ameba (Entamoeba histolytica), a single-celled parasite transmitted to humans via contaminated water and food. E. histolytica has the ability to penetrate the gut wall and cause abscesses in the liver – often a fatal event. Entamoeba coli is a more subtle parasite which does not penetrate the gut wall. It is not a fulminating disease and thus often goes undiagnosed. It is a common parasite in the United States infecting many unsuspecting people.