What causes sudden severe pain below the lower abdomen, and what should be done?

　　Sudden severe pain below the lower abdomen may be caused by intestinal spasms, ovulation pain, acute enteritis, ureteral stones, pelvic inflammatory disease, and other conditions. Symptoms can be improved through rest, keeping warm, dietary adjustments, and medication. If the pain persists or is accompanied by fever or vomiting, prompt medical attention is necessary.

　　1. Intestinal Spasms: Caused by cold exposure to the abdomen or dietary irritation leading to intense contractions of the intestinal smooth muscle, resulting in paroxysmal severe abdominal pain, possibly accompanied by bloating. It is recommended to rest immediately, apply a hot water bottle to the abdomen, avoid strenuous activity, and refrain from consuming raw, cold, or spicy foods temporarily.

　　2. Ovulation Pain: During the ovulation period in women, rupture of the ovarian follicle releases a small amount of fluid that irritates the peritoneum, causing brief, sharp pain on one side of the lower abdomen. It is advised to rest in bed, avoid pressing on the abdomen, keep the abdominal area warm, and the pain usually resolves on its own.

　　3. Acute Enteritis: Consuming contaminated food leads to bacterial or viral infection of the intestines, causing intestinal inflammation with severe abdominal pain, diarrhea, nausea, and vomiting. Under medical guidance, medications such as montmorillonite powder, cefixime granules, and oral rehydration salts may be used to relieve symptoms.

　　4. Ureteral Stones: Stones blocking the ureter cause urinary tract obstruction, leading to severe colicky pain in the lower abdomen, often accompanied by frequent urination and hematuria. Under medical guidance, medications such as diclofenac sodium sustained-release tablets, lithotripsy granules, and anisodamine tablets may be used to alleviate symptoms.

　　5. Pelvic Inflammatory Disease: Bacterial infection of pelvic tissues causes acute inflammation, pelvic congestion, and edema, resulting in severe lower abdominal pain, fever, and abnormal vaginal discharge. Follow medical advice to use medications such as cefuroxime axetil tablets, metronidazole tablets, and fuyankang capsules to improve symptoms.

　　Maintain good dietary hygiene and avoid unclean food, keep the abdomen warm to prevent cold exposure, maintain regular作息 (作息 means "work-rest schedule" or "daily routine"), avoid excessive fatigue, engage in moderate exercise to strengthen physical health, and promptly adjust your condition to relieve discomfort when pain occurs.