The work of doctors often brings surprises. The author once encountered a case of a young female patient with right lower abdominal pain for many years and an unknown diagnosis, who finally had no choice but to have her appendix removed, and no inflammatory changes of the appendix were seen intraoperatively, and finally a 5px celery stick was found in the cavity by cutting open the appendix. Acute appendicitis is a common surgical disease with rapid onset, especially in the elderly and young children, and can cause serious consequences such as peritonitis, shock or even death if not treated appropriately and in a timely manner. Causes of appendicitis: appendiceal obstruction including fecal stone obstruction, obstruction due to appendiceal spasm caused by seasonal change of diet; infection by exogenous endogenous bacteria; other causes such as appendiceal dysplasia, impaired blood supply, appendiceal or appendix tumor secondary to appendiceal inflammation, etc. Clinical manifestations: Typical appendicitis is characterized by early pain in the upper abdomen or in an inaccurate location, accompanied by nausea and discomfort, which gradually shifts to the right lower abdomen as the disease evolves. As the disease progresses, the symptoms of appendiceal perforation will worsen, showing diffuse pain in the whole abdomen, rebound pain with pressure pain in the whole abdomen, fever, diarrhea and even shock. Ancillary tests: laboratory tests suggest elevated leukocyte neutrophils, ultrasound CT reveals an enlarged appendix, and for chronic appendicitis, barium enema examination is the current gold standard. Treatment: Acute appendicitis is diagnosed clearly and surgery is indicated, but non-surgical treatment can be taken first to delay surgery because the patient’s circumstance or objective conditions do not allow it. If acute appendicitis has combined with limited peritonitis and formed a periappendiceal abscess, non-surgical treatment should also be used to make the inflammatory mass absorb, and then consider elective appendectomy.