Pain in the lower left abdomen most commonly comes from the sigmoid colon, the S-shaped final section of your large intestine that sits in that exact spot. The cause can range from something as harmless as trapped gas to something that needs prompt medical attention, like diverticulitis. What’s actually going on depends on how the pain feels, how long it lasts, and what other symptoms come with it.
What’s in the Lower Left Abdomen
The sigmoid colon is the dominant structure in this area, and it’s responsible for the majority of lower left abdominal pain. The left ureter, which carries urine from your kidney to your bladder, also runs through this region. In women, the left ovary and fallopian tube sit here as well, which adds several possible causes that don’t apply to men. Muscles and connective tissue of the abdominal wall can also be the source, particularly after physical activity or strain.
Trapped Gas and Constipation
The most common and least worrisome explanation is gas or stool building up in the sigmoid colon. Because the colon bends sharply in this area, gas can get trapped at those bends and cause surprisingly intense, localized pain. Johns Hopkins describes a condition called splenic-flexure syndrome, a chronic pattern where gas collects on the left side of the colon and causes pain that some people initially mistake for a heart problem.
Constipation works similarly. When stool backs up in the sigmoid colon, it stretches the walls and triggers cramping. This pain tends to come in waves, feels better after passing gas or having a bowel movement, and doesn’t come with fever or vomiting. If this describes your situation, it’s likely nothing dangerous, though recurring episodes are worth mentioning to your doctor.
Diverticulitis
Diverticulitis is one of the most important causes to know about because it’s common, it’s treatable, and it almost always shows up in the lower left abdomen. Small pouches called diverticula form in the colon wall over time, especially in the sigmoid colon. When one of those pouches becomes inflamed or infected, the result is diverticulitis.
The pain is usually sudden and intense, though it can also start mild and gradually worsen over several hours. It tends to stay in one spot rather than moving around. Alongside the pain, you may notice tenderness when you press on the area, fever, nausea, or a sudden change in bowel habits (either diarrhea or constipation). Diverticulitis becomes more common after age 40 and is one of the first things doctors consider when someone presents with left-sided abdominal pain and fever.
A CT scan is the gold standard for diagnosing diverticulitis, with a diagnostic accuracy of about 98% according to the American College of Radiology. Mild cases are often treated at home with a course of antibiotics and a temporary change in diet. Complicated cases involving an abscess or perforation may require hospitalization.
IBS and Inflammatory Bowel Disease
Irritable bowel syndrome (IBS) frequently causes cramping pain in the lower left abdomen because the sigmoid colon is where contractions are strongest. The underlying issue appears to involve uncoordinated intestinal contractions and hypersensitive nerves in the gut, though the exact cause isn’t fully understood. IBS pain typically comes with diarrhea, constipation, or an alternating pattern of both. It often improves after a bowel movement and tends to flare during periods of stress or after eating certain foods. IBS doesn’t cause visible inflammation or lasting damage to the intestine.
Inflammatory bowel disease, specifically ulcerative colitis, is a different situation. Here, the immune system attacks the lining of the digestive tract, causing chronic inflammation. The symptoms can overlap with IBS (cramping, diarrhea, abdominal pain), but IBD also causes bloody bowel movements, fevers, and weight loss. Unlike IBS, IBD can lead to serious complications and sometimes requires surgery. If your lower left pain comes with blood in your stool or unexplained fevers, that distinction matters.
Kidney Stones
A stone that forms in the left kidney and travels down the left ureter can produce pain that radiates into the lower left abdomen. This pain is distinctive: it comes in severe waves, often starting in the back or side below the ribs and spreading downward into the lower belly and groin. Most people describe it as the worst pain they’ve ever felt. It typically comes with nausea, an urgent need to urinate, or blood in the urine. The wave-like pattern, called renal colic, happens as the ureter spasms around the stone trying to push it toward the bladder.
Ovarian Causes in Women
For women, the left ovary and fallopian tube add several possibilities. A ruptured ovarian cyst can cause sudden, sharp pain on the left side. Ovarian torsion, where the ovary twists on its blood supply, causes severe pain that doesn’t let up. An ectopic pregnancy in the left fallopian tube is a medical emergency that produces lower left pain along with missed periods and vaginal bleeding. For premenopausal women with lower left pain, the American College of Radiology recommends starting with a pelvic ultrasound if there’s any clinical concern for a gynecologic cause.
Hernias and Muscle Strain
Not all lower left pain comes from inside the abdomen. An inguinal hernia occurs when fatty tissue or a loop of intestine pushes through a weak spot in the abdominal wall into the groin area. The key distinguishing feature is a visible or palpable lump beneath the skin, something you won’t find with internal organ pain. Hernia pain often presents as a dull ache or burning sensation, especially when standing, coughing, or lifting. The pain may come and go, but the hole in the abdominal wall won’t close on its own.
A muscle strain in the abdominal wall or groin area is usually easier to identify because you’ll often remember the moment it happened, sometimes with a popping sensation. The pain worsens with specific movements and feels sore to the touch. It typically resolves within days to weeks with rest.
A Less-Known Mimic: Epiploic Appendagitis
About 5% of people initially diagnosed with diverticulitis or appendicitis actually have epiploic appendagitis instead. This happens when one of the small fat-filled pouches on the outside of the colon loses its blood supply and becomes inflamed. It causes sharp, localized pain that can feel identical to diverticulitis, but it’s a benign condition that resolves on its own. Treatment is simply pain relief with anti-inflammatory medication, and surgery is rarely needed. The inflamed tissue eventually calcifies and breaks off, ending the episode. It’s worth knowing about because it can save you from unnecessary antibiotics or procedures if correctly identified on a CT scan.
When Lower Left Pain Is an Emergency
Most lower left abdominal pain resolves on its own or with simple treatment. But certain combinations of symptoms warrant an emergency room visit. Pain so severe it prevents you from functioning normally, pain accompanied by vomiting where you can’t keep liquids down, complete inability to pass gas or have a bowel movement (especially if you’ve had prior abdominal surgery, which raises the risk of bowel obstruction), and abdominal swelling with a rapid pulse all qualify.
For hernias specifically, the most dangerous scenario is strangulation, where trapped intestine loses its blood supply. This causes severe groin pain, nausea, and vomiting, and requires emergency surgery. If you have a known hernia and develop sudden, worsening pain at the site, treat it as urgent.
Fever combined with worsening tenderness is another red flag. While a low-grade fever with mild pain might indicate uncomplicated diverticulitis that your doctor can manage in an outpatient setting, high fever with severe tenderness could signal a perforation or abscess that needs immediate care.