Pain in the lower abdomen is usually considered appendicitis. Appendicitis can cause pain in the lower and middle abdomen or in the right lower abdomen. The pain is especially pronounced in the right lower abdomen and is associated with pressure and localized muscle tension, especially when standing up, and the pain is aggravated by abdominal muscle exertion. If the pain is diagnosed as appendicitis, an appendectomy is required. The pain may also be caused by a lesion in the colon, such as a colon tumor, which can lead to pain in the lower abdomen, usually accompanied by thinning stools, increased frequency of stools and bloody stools. If necessary, colonoscopy and abdominal CT can be done, and if the abdominal pain is diagnosed to be caused by colon cancer, radical surgery is recommended.