Pain in the lower left part of your abdomen most often comes from the sigmoid colon, the S-shaped segment of your large intestine that sits in that area. But several other structures live there too, including the left ureter (the tube connecting your kidney to your bladder) and, in women, the left ovary and fallopian tube. The cause can range from something as simple as trapped gas to conditions that need prompt medical attention, so the character of the pain, how it started, and what other symptoms you have all matter.
Diverticulitis: The Most Common Serious Cause
Diverticulitis is the condition most closely associated with lower left abdominal pain. It happens when small pouches that form in the colon wall become inflamed or infected. The pain is typically constant, not crampy, and it tends to settle specifically in the lower left side. You may also have a fever, a change in your bowel habits, or notice mucus or blood when you go to the bathroom.
The pouches themselves (called diverticula) become increasingly common with age. Up to 65% of people over 65 have them, though most never cause problems. The condition used to be rare in younger adults, but recent years have seen a sharp rise in people under 40 developing it. A CT scan is the gold-standard test for confirming the diagnosis and checking for complications like abscesses or perforations.
Treatment has shifted in recent years. Current guidelines recommend that if you’re otherwise healthy, not immunocompromised, and the case is uncomplicated, you likely don’t need antibiotics. Studies show that skipping antibiotics in these straightforward cases doesn’t lead to worse outcomes or higher complication rates. Antibiotics are reserved for people who are systemically unwell, have immune system problems, or develop complications. Most uncomplicated cases resolve with rest, a temporary change in diet, and pain management.
Constipation and Irritable Bowel Syndrome
The sigmoid colon is the last stop before stool reaches your rectum, which makes the lower left abdomen a common site for pain related to constipation and IBS. When bowel movements slow down, hard stool accumulates in this section, stretching the colon wall and triggering cramping. In some people, the muscles responsible for coordinating a bowel movement don’t work in sync, which reduces emptying of the left colon specifically and leads to pain, bloating, or a feeling of fullness on that side.
This type of pain tends to come and go, often worsening after meals and improving after a bowel movement or passing gas. It’s usually more of a dull ache or pressure rather than a sharp, constant pain. If you notice a pattern where the discomfort tracks with how recently you’ve had a bowel movement, constipation or IBS is a likely explanation. The accumulation of stool and gas creates a cycle: distension triggers discomfort, discomfort slows motility further, and the backup worsens.
Kidney Stones and the Left Ureter
A kidney stone that moves from the kidney into the left ureter can produce pain that radiates into the lower left abdomen and groin. This pain is notoriously intense. It happens because the stone blocks urine flow, causing the kidney to swell and the ureter to spasm around it. The pain often comes in waves, and you may notice blood in your urine, nausea, or a frequent urge to urinate even when your bladder isn’t full.
What makes kidney stone pain distinctive is its movement. It often starts in the back or flank and migrates downward toward the lower abdomen and groin as the stone travels through the ureter. If the pain started higher up and has been shifting, a stone is worth considering. Ultrasound can detect the obstruction, though CT is more sensitive for finding the stone itself, especially when it’s lodged in the ureter.
Ovarian Cysts and Endometriosis in Women
In women, the left ovary and fallopian tube sit in the lower left quadrant, and problems with either can produce pain that feels identical to a digestive issue. Ovarian cysts are fluid-filled sacs that often form during the menstrual cycle and resolve on their own. But if a cyst ruptures, twists, or becomes infected, the pain can be sudden and severe. Ruptured cysts are by far the most common complication, accounting for roughly two-thirds of cases that progress to acute symptoms.
Endometriosis affecting the ovary can also cause sharp, sudden lower abdominal pain. Key features include severe pain at onset that may partially ease after the initial spike, tenderness around the ovary, and a history of painful periods. Fever and gastrointestinal symptoms like nausea or changes in bowel habits can show up too, which is part of why these cases are sometimes mistaken for diverticulitis or appendicitis. If your lower left pain seems to track with your menstrual cycle or comes with unusual period symptoms, a gynecological cause is worth investigating.
Inguinal Hernias
An inguinal hernia occurs when tissue pushes through a weak spot in the abdominal wall near the groin. In men, this weak spot is the canal where the spermatic cord passes into the scrotum. The hallmark sign is a visible or palpable bulge near the pubic bone that becomes more obvious when you stand up, cough, or strain. The pain tends to be a pressure or aching sensation in the groin that worsens with bending, lifting, or coughing.
In men, larger hernias can extend into the scrotum, causing swelling and more noticeable pain. A hernia that can’t be pushed back in, or one accompanied by sudden severe pain, nausea, and vomiting, may be incarcerated or strangulated, which cuts off blood flow to the trapped tissue and requires emergency treatment.
A Condition That Mimics Diverticulitis
Epiploic appendagitis is a rare condition that closely mimics diverticulitis but is far less serious. It happens when one of the small fat-filled pouches on the outside of the colon loses its blood supply and becomes inflamed. The pain comes on suddenly, and you can usually point to the exact spot that hurts. About 5% of people initially diagnosed with diverticulitis or appendicitis actually have epiploic appendagitis instead.
The good news is that it resolves on its own. The inflamed tissue eventually calcifies and detaches, which stops the inflammation. Treatment is just pain relief while you wait it out. The main risk is unnecessary treatment for a more serious condition it resembles, which is why imaging can be helpful in distinguishing the two.
Signs That Need Immediate Attention
Most lower left abdominal pain turns out to be something manageable, but certain patterns warrant an emergency room visit. Pain so severe that it interrupts your ability to function, vomiting that won’t stop or prevents you from keeping liquids down, complete inability to have a bowel movement combined with severe pain, or pain that resembles something you’ve experienced before but is noticeably worse or different this time are all reasons to seek immediate care. Fever combined with worsening abdominal pain is another signal that something may be progressing.
If you’ve had previous abdominal surgery, that history changes the landscape of possible causes, including adhesions or internal scar tissue that can trap the bowel. Swelling in the abdomen, an inability to pass gas, or a rapid pulse alongside the pain all suggest something more urgent may be happening.