Lower right abdominal pain in men can be caused by diseases such as acute appendicitis, mesenteric lymphadenitis, ureteral stones, or other diseases such as ulcerative colitis. 1. Acute appendicitis: Acute appendicitis is caused by obstruction of the appendiceal cavity and bacterial invasion. The main symptoms of patients are right lower abdominal pain, vomiting, fatigue, abdominal distension and so on, so male patients will have metastatic right lower abdominal pain. 2. Mesenteric lymphadenitis: mesenteric lymphadenitis is mainly caused by viral, bacterial and parasitic infections. Patients will have fever, right lower abdominal pain, vomiting and other symptoms, therefore, male patients will have right lower abdominal pain and other manifestations. 3. Ureteral stones: Ureteral stones are caused by kidney stones staying in the ureter during the process of kidney stone discharge. Patients mainly manifest renal colic, hematuria, urinary urgency, anuria, etc., which will lead to the symptoms of lower right abdominal pain. 4. Other: ulcerative colitis, Crohn’s disease, intestinal tuberculosis and other diseases may also cause male patients to have lower right abdominal pain and other manifestations. Male patients with symptoms of lower right abdominal pain should promptly identify the cause of the disease, and follow the doctor’s instructions for treatment.