Abstract:Macaques are very important and precious laboratory animals. The aim of this study was to examine the entire colon on alive macaques repeatedly. In order that,it is particularly important to establish a method about colon preparation before colonoscopy. But until now there are no reports on specific preparation method for colonoscopy on macaques. The aim of this study was to develop a method of bowel preparation before colonoscopy on macaques. Thirty macaques were fed with glauber’ s salt through nasogastric tubes several times before colonoscopy. Intestinal cleansing was observed by colonoscopy. Three macaques were prepared for grade Ⅲ and the rest of the macaques were grade Ⅰ and grade Ⅱ . All macaques did not have serious complications such as dehydration, shock, and death during the process of washing the intestines. The colonoscopy was successfully completed on intestinal preparations of grade Ⅰ and grade Ⅱ macaques.