A slightly swollen appendix may have acute simple appendicitis. Acute simple appendicitis may be present when the appendix is mildly swollen with mild vague pain or paroxysms of sharp pain and distension in the abdomen. The lesions are mostly confined to the mucosa and submucosa, the appendix has a mildly swollen appearance, the plasma membrane is congested and loses its normal luster, and there is a small amount of fibrinous exudate on the surface, which is in the early stage of appendicitis. There may be nausea, anorexia, vomiting, generalized weakness and other symptoms, due to the mild symptoms, may be overlooked. In general, once appendicitis is diagnosed, appendectomy should be performed as soon as possible to remove the appendix. Early surgery can prevent further progression of appendicitis and also minimize the occurrence of immediate and long-term complications. It is recommended to seek prompt medical attention for a definitive diagnosis to avoid delays.