Abdominal pain is the single most common reason people visit the emergency department in the United States, holding that rank every year from 2016 through 2022. That’s because the abdomen contains so many organs packed closely together that dozens of conditions, from mild gas to serious surgical emergencies, can produce pain in roughly the same area. The good news: most causes are not dangerous. But figuring out what’s behind your pain starts with paying attention to exactly where it hurts, what kind of pain it is, and what other symptoms come with it.
Where the Pain Is Matters
Your abdomen is roughly divided into four quadrants, and each one houses different organs. Pain in a specific area often points toward a short list of likely causes.
Upper right: This is where your gallbladder and liver sit. Pain here frequently comes from gallstones or gallbladder inflammation, especially if it flares after fatty meals. Liver problems, kidney stones on the right side, and even pneumonia can also cause pain in this area.
Upper left: Stomach-related problems like gastritis (irritation of the stomach lining) and ulcers tend to show up here, along with pancreas inflammation. More concerning possibilities include heart-related pain. A heart attack can produce upper left abdominal discomfort, particularly in women and older adults who may not have the classic chest-clutching presentation.
Lower right: The big concern here is appendicitis, but this quadrant also covers conditions like irritable bowel syndrome, inflammatory bowel disease, kidney stones, and in women, ovarian cysts or ectopic pregnancy.
Lower left: Diverticulitis, a condition where small pouches in the colon wall become inflamed, is one of the most common causes of lower left pain, especially in people over 50. IBS, IBD, kidney stones, and gynecological conditions also produce pain here.
Pain that’s hard to pinpoint, or that seems to spread across your whole belly, is called diffuse or nonlocalized pain. This can come from something as routine as a stomach virus or as serious as a bowel obstruction.
The Most Common Digestive Culprits
For most people searching this question, the answer turns out to be something happening in the digestive tract. A few conditions account for the majority of cases.
Gas and bloating are the most frequent and least worrisome cause. Swallowed air, high-fiber foods, carbonated drinks, and certain food intolerances (especially lactose and fructose) can produce sharp, crampy pains that move around and improve after passing gas or having a bowel movement.
Gastritis and acid reflux cause a burning or gnawing pain in the upper abdomen, often worse on an empty stomach or after spicy or acidic foods. If you notice the pain worsening when you lie down or bend over, reflux is a likely contributor.
Irritable bowel syndrome affects roughly 10 to 15 percent of people worldwide and causes cramping, bloating, and changes in bowel habits. IBS does not cause inflammation or physical damage to the digestive tract, which is the key difference between it and inflammatory bowel disease. IBD, which includes Crohn’s disease and ulcerative colitis, is an autoimmune condition that causes real tissue damage, can affect organs beyond the gut, and often produces bloody stools, weight loss, and fatigue alongside pain.
Constipation is an underappreciated cause of abdominal pain. When stool backs up, it can produce cramping across the lower abdomen that people sometimes mistake for something more serious. If you haven’t had a bowel movement in a few days and your lower belly feels full and tender, this is worth considering first.
Causes That Aren’t Digestive
Not all abdominal pain originates in the gut. Several organs outside the digestive system can produce pain that feels like a stomach problem.
Kidney stones cause intense, wave-like pain that typically starts in the flank (your side, just below the ribs) and radiates toward the lower abdomen and groin. The pain comes and goes in waves, and you may notice blood in your urine or a frequent urge to urinate. A kidney infection produces similar flank pain but adds fever and sometimes nausea.
Pneumonia in the lower lobes of the lungs can cause upper abdominal pain, particularly on the right side. If your abdominal pain came on alongside a cough, fever, or difficulty breathing, the lungs may be the real source.
Heart problems, especially in women and older adults, sometimes present as upper abdominal pain rather than obvious chest pain. This is worth knowing because it can delay people from seeking the right kind of help.
Abdominal Pain Specific to Women
The reproductive organs sit in the lower abdomen, and several gynecological conditions produce pain that overlaps with digestive symptoms.
Ovarian cysts often cause one-sided lower abdominal pain that may radiate to the lower back. Most cysts resolve on their own, but a ruptured cyst causes sudden, sharp pain that can be severe. Ovarian torsion, where an ovary twists on its blood supply, is a surgical emergency with sudden, intense pain and nausea.
Endometriosis occurs when tissue similar to the uterine lining grows outside the uterus. It causes chronic pain that tends to worsen with menstrual cycles, though it can produce discomfort at any time. The pain results from inflammation and adhesions that form at the sites where this tissue grows.
Pelvic inflammatory disease, usually caused by a sexually transmitted infection, produces bilateral (both sides) lower abdominal pain along with abnormal vaginal bleeding and sometimes fever. An ectopic pregnancy, where a fertilized egg implants outside the uterus, is a medical emergency that causes lower abdominal pain in early pregnancy, often with vaginal bleeding and dizziness.
How Appendicitis Pain Progresses
Appendicitis deserves its own section because it’s common, time-sensitive, and follows a recognizable pattern. The pain typically starts as a vague ache around the belly button within the first 12 to 18 hours. Over the next several hours, it migrates to the lower right abdomen and becomes sharper and more localized. The classic tender spot sits about one-third of the way from the hip bone to the belly button.
The window before a ruptured appendix is generally 30 to 36 hours from the start of symptoms. After rupture, the pain may briefly improve before spreading across the entire abdomen as infection sets in. Nausea, loss of appetite, and a low-grade fever often accompany the pain. If your pain follows this migration pattern, especially if it hurts more when you walk, cough, or press on the lower right side, seek emergency care promptly.
Age Changes the Picture
Abdominal pain presents differently at different stages of life. In older adults, symptoms tend to be more vague and less dramatic, which can be dangerously misleading. Someone over 65 with appendicitis receives the correct initial diagnosis only about half the time, and rates of rupture and complications are significantly higher compared to younger patients. Older adults with abdominal pain are twice as likely to need surgery as younger people with the same complaint.
Mesenteric ischemia, where blood flow to the intestines is reduced, is uncommon but serious and occurs almost exclusively in older patients with heart disease or blood vessel problems. The hallmark is severe pain that seems out of proportion to what the doctor can find on exam. Early symptoms can mimic a stomach bug, with nausea, vomiting, and diarrhea, but the condition can progress to bowel damage if not caught. Anyone over 50 with new, severe abdominal or back pain should also have a large blood vessel aneurysm considered as a possible cause.
When Abdominal Pain Needs Emergency Care
Most abdominal pain resolves on its own or with simple treatment. But certain features signal something that needs immediate attention:
- Rigid or distended abdomen: a belly that feels hard, board-like, or visibly swollen
- Severe pain with guarding: pain so intense you can’t let anyone touch your stomach
- Signs of internal bleeding: vomiting blood, black or tarry stools, or dizziness with pale skin
- Bilious vomiting: vomit that’s green or yellow-green, suggesting a possible bowel obstruction
- Pain after abdominal trauma: even if the pain seems mild initially
- Fainting or near-fainting
- Pregnancy with abdominal pain: ectopic pregnancy must be ruled out
- Fever with severe pain: suggests infection that may need urgent treatment
What to Expect at the Doctor’s Office
If your pain leads to a medical visit, the evaluation typically starts with a detailed history: where the pain is, when it started, what makes it better or worse, and what other symptoms you have. A physical exam follows, with the doctor pressing on different areas of your abdomen to locate tenderness.
Imaging depends on the suspected cause and pain location. For upper right abdominal pain, an ultrasound is usually the first choice because it’s excellent at spotting gallbladder problems. For lower abdominal pain on either side, a CT scan is typically preferred because it gives a clearer picture of the appendix, colon, and surrounding structures. When the pain doesn’t localize clearly, CT is generally the go-to if the doctor suspects something serious. For pregnant patients, ultrasound and MRI are used first to avoid radiation exposure, with CT reserved for situations where those options aren’t enough.
Blood and urine tests help narrow the possibilities. A complete blood count can reveal signs of infection or blood loss, while a urine test can quickly identify kidney stones or urinary tract infections. In women of reproductive age, a pregnancy test is standard before any imaging.