Amebiasis is an infection with amoebas (a type of protozoan), particularly Entamoeba histolytica. The disease is contracted by eating food or drinking water that has been infected with encysted forms of the amoebas. The symptoms include diarrhea, weakness, and sometimes jaundice. During the course of the disease, sores and abscesses form on the mucous membrane of the large intestine (sometimes causing perforations), and the abscesses may be carried to the liver via the portal vein. Patients are usually treated with drugs called metronidazole (Flagyl) and chloroquinine; they may need to be medicated for up to three months to clear the infection.