Lower left abdominal pain most often comes from the digestive system, specifically the part of your colon that runs down the left side of your body and curves sharply before connecting to your rectum. This area houses your descending colon, sigmoid colon, portions of your small intestine, 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 pattern and severity of your pain matter a lot in narrowing things down.
Trapped Gas and Constipation
The most common and least serious explanation is gas or stool building up in your colon. Your colon makes a sharp bend on the left side of your abdomen, right below your ribs, called the splenic flexure. Gas traveling through your digestive tract can get stuck at this bend, especially when there’s a lot of it. Think of water rushing toward a sharp curve in a river: too much volume overwhelms the turn. This can cause bloating, fullness, nausea, and sharp pain in your upper or lower left abdomen. Some people are born with an unusually tight bend in their colon, making them more prone to this.
Constipation produces a similar effect lower down. When stool backs up in the sigmoid colon (the S-shaped section just above your rectum), it stretches the colon wall and triggers cramping pain on the lower left side. This type of pain usually improves after a bowel movement and worsens when you haven’t gone in a day or two. If your pain comes and goes, feels like pressure or cramping, and resolves with passing gas or stool, this is likely your answer.
Diverticulitis
Diverticulitis is one of the most well-known causes of lower left abdominal pain, particularly in adults over 40. Small pouches called diverticula form along the colon wall over time, and when one of these pouches becomes inflamed or infected, the result is a steady, localized pain on the lower left side. Tenderness that’s isolated to just the lower left quadrant is the most telling sign, making diverticulitis about ten times more likely than other diagnoses. Fever supports the diagnosis, and notably, vomiting is uncommon with diverticulitis, which helps distinguish it from other abdominal emergencies.
The condition has become more common over recent decades. Only 1% to 4% of people who have diverticula ever develop diverticulitis, but when it strikes, it tends to be memorable. The pain is usually constant rather than crampy, and it can last for days if untreated.
Treatment has shifted in recent years. Growing evidence shows that uncomplicated diverticulitis (meaning no abscess, perforation, or signs of widespread infection) often resolves with pain management alone, without antibiotics. A major clinical trial of 480 patients found no significant difference in outcomes between those treated with antibiotics and those given only pain relievers. Pain control was actually better in the group that skipped antibiotics. That said, antibiotics are still recommended if you have significant other health conditions, a weakened immune system, or signs of a more serious infection like high fever or severe tenderness across your whole abdomen.
Irritable Bowel Syndrome
IBS is a chronic condition that frequently targets the lower left abdomen because the sigmoid colon is one of the most sensitive and active parts of the digestive tract. The hallmark of IBS is recurring abdominal pain that’s tied to bowel habits: your pain tends to flare after large meals or during stressful periods, and it often improves temporarily after a bowel movement. You may alternate between constipation and diarrhea, notice mucus in your stool, or feel bloated and gassy.
IBS doesn’t cause visible inflammation or damage to your intestines, which is what separates it from inflammatory bowel disease (IBD) like Crohn’s disease or ulcerative colitis. If your pain comes with bleeding, unexplained weight loss, persistent fever, or anemia, those are signs of IBD rather than IBS. A general guideline for IBS diagnosis is abdominal discomfort for at least 12 weeks over a 12-month period, along with pain that’s relieved by defecation or linked to changes in how often you go or what your stool looks like.
Kidney Stones
A stone that forms in your left kidney and moves into the ureter (the tube draining urine from kidney to bladder) can produce intense pain that radiates to your lower left abdomen. The pain isn’t actually from the stone itself but from urine backing up into the kidney once the stone blocks the ureter. Your kidney isn’t a stretchy organ, so when it swells, the nerves on its surface become severely irritated.
This pain typically starts in your middle back on the left side, between your ribs and pelvis, then moves forward and downward toward your abdomen and groin. It tends to come in waves, can be excruciating, and is often accompanied by nausea, blood in the urine, or a frequent urge to urinate. If your lower left pain started in your back and migrated forward, a kidney stone is a strong possibility.
Hernias
A left-sided inguinal hernia can cause pain in the lower left abdomen near the groin. This happens when tissue (usually part of the intestine or fatty tissue) pushes through a weak spot in the abdominal wall. The pain often feels like a burning, gurgling, or aching sensation that gets heavier toward the end of the day or after prolonged physical activity. You may notice a visible bulge in the groin area that disappears when you lie down.
If the pain is worse when you cough, strain, or lift something heavy, and you can see or feel a soft lump near your groin crease, a hernia is worth investigating.
Causes Specific to Women
The left ovary and fallopian tube sit in the lower left abdomen, so several gynecological conditions can produce pain in this area. An ovarian cyst on the left side can cause dull or sharp pain, especially if it ruptures or twists. Ectopic pregnancy, where a fertilized egg implants in the left fallopian tube instead of the uterus, causes sharp, sudden pain and is a medical emergency. Endometriosis can also produce chronic lower left pain that tends to worsen around menstruation. If your pain seems to follow your menstrual cycle or you could be pregnant, these causes move to the top of the list.
How Doctors Figure Out the Cause
When you see a provider for lower left abdominal pain, the physical exam focuses on where exactly your tenderness is, whether your abdomen is rigid, and whether pain worsens with pressure or release. For suspected diverticulitis, a CT scan is the preferred test, with sensitivity and specificity reported as high as 100% for confirming the diagnosis. CT also has the advantage of revealing alternative diagnoses that can mimic diverticulitis, like ovarian problems, hernias, or bowel obstruction.
Ultrasound is another effective initial tool. A large analysis comparing ultrasound and CT found no statistically significant difference between the two in diagnosing acute diverticulitis, though ultrasound is more operator-dependent and can be limited in patients with a larger body size. For groin pain where a hernia is suspected but can’t be felt on exam, MRI has sensitivity and specificity above 95%.
Warning Signs That Need Urgent Attention
Most lower left abdominal pain resolves on its own or with simple treatment, but certain patterns signal something more serious. Seek care promptly if your pain is sudden and severe, if it persists or steadily worsens over hours, if your abdomen feels rigid or distended, or if you notice blood in your urine or stool. Persistent fever, inability to keep food down for days, or not having a bowel movement for several days also warrant evaluation. If you’re pregnant and experiencing lower left pain, treat it as urgent regardless of severity.