Appendicitis is a common and potentially serious condition where the appendix becomes inflamed, often due to a blockage or infection. It typically presents with sudden pain starting around the belly button and shifting to the lower right abdomen, along with nausea, vomiting, loss of appetite, and fever. If left untreated, the appendix may rupture, leading to peritonitis or sepsis. Diagnosis involves clinical examination, blood tests, and imaging (ultrasound or CT scan). Treatment usually requires surgical removal of the appendix (appendicectomy). Recognizing symptoms early can prevent complications and improve recovery.