Four cases of amebic colitis diagnosed immediately by cytological examination of biopsy specimen under colonoscopy. The patients were three men and a woman, 28-49 years old. They visited to our hospital with complaint of blood stool. Colonoscopy showed a round ulceration covered with the yellow-whitish exudates, surrounded by normal mucosa close to the orifice of the appendix, and multiple erosions and small ulcers in the rectum. Cytological examination of biopsy specimen from the ulcer revealed amebic organism. Ten days eradication therapy of Metronidazole successfully carried out. This cytological method is useful technique to facilitate early diagnosis of amebic colitis.
