Pain in your lower left abdomen most commonly comes from the digestive system, specifically the sigmoid colon, which is the S-shaped segment of your large intestine that sits in that exact spot. But several other organs live in that area too, including portions of the small intestine, the left ureter (the tube connecting your kidney to your bladder), and in women, the left ovary and fallopian tube. The cause of your pain depends on how it feels, how long it’s lasted, and what other symptoms come with it.
Gas and Constipation
The most common and least serious explanation is trapped gas or constipation. The sigmoid colon is the last major bend before your rectum, and gas or stool can build up there, creating a crampy, bloated feeling on your lower left side. This kind of pain tends to come and go, sometimes shifting in location, and often improves after passing gas or having a bowel movement.
If gas is a recurring problem, eating smaller and more frequent meals can help. So can slowing down while you eat, avoiding carbonated drinks, skipping chewing gum and hard candy, and cutting back on foods that tend to produce gas for you personally. Over-the-counter remedies like simethicone can offer short-term relief.
Diverticulitis
Diverticulitis is one of the most well-known causes of lower left abdominal pain, especially in adults over 40. It happens when small pouches that form in the wall of the colon (called diverticula) become inflamed or infected. The pain is typically steady rather than crampy, often worsens over a day or two, and may come with fever, nausea, or a change in bowel habits.
Most cases are uncomplicated, meaning there’s no abscess, perforation, or obstruction. Current guidelines from the American Gastroenterological Association and several other major medical societies now recommend managing uncomplicated diverticulitis with pain control and a liquid diet, without antibiotics. A large randomized trial (the DINAMO trial) found that patients treated without antibiotics had virtually the same outcomes as those who received them, with similarly low rates of return visits and hospitalization. Antibiotics are still used when someone has a weakened immune system, significant other health conditions, or signs of a more severe infection.
Complicated diverticulitis, which involves perforation, bleeding, or abscess, is less common but more serious. Symptoms lasting more than five days, vomiting, and signs of widespread infection raise concern for this progression.
Irritable Bowel Syndrome
If your lower left pain is chronic, recurring, and tied to your bowel habits, irritable bowel syndrome (IBS) is a strong possibility. IBS is diagnosed when you’ve had abdominal pain for at least 12 weeks over the past year, along with at least two of the following: the pain improves after a bowel movement, it started around the same time your stool frequency changed, or it started when the appearance of your stool changed.
IBS pain often flares after large meals or during periods of stress. It does not cause inflammation, bleeding, weight loss, or fever. If you’re experiencing any of those, the concern shifts to inflammatory bowel disease (IBD), such as ulcerative colitis, which can cause destructive inflammation and permanent damage to the intestines. That distinction matters, because IBD requires very different treatment.
Kidney Stones
A stone moving through your left ureter can cause intense pain that starts in your side and back below the ribs, then radiates down into your lower abdomen and groin. This pain is distinctive: it comes in waves, shifts in location as the stone moves, and can be severe enough that you can’t sit still. You may also notice burning during urination, pink or red urine, or a frequent urge to urinate.
Kidney stone pain doesn’t typically improve with changes in position or after a bowel movement, which helps distinguish it from digestive causes.
Ovarian and Reproductive Causes
In women, the left ovary and fallopian tube sit in the lower left abdomen, and several gynecological conditions can cause pain there. Ovarian cysts are common and often resolve on their own, but larger cysts or those that rupture can cause sudden, sharp pain along with weakness and fever.
Endometriomas, sometimes called “chocolate cysts,” are cysts on the ovary caused by endometriosis. Pelvic pain or tenderness is the most common symptom, and it can happen at any time, not just during your period. Other signs include very painful periods, pain during sex, pain while urinating or having a bowel movement, bloating, and back pain. Endometriomas are usually a sign of more advanced endometriosis and can lead to complications including infertility from scar tissue and inflammation affecting the ovaries and fallopian tubes.
An ectopic pregnancy, where a fertilized egg implants outside the uterus (most often in a fallopian tube), can also cause lower abdominal pain on one side. This is a medical emergency. If there’s any chance you could be pregnant and you’re having one-sided pelvic pain, especially with vaginal bleeding or dizziness, seek immediate care.
Inguinal Hernia
A hernia on the left side of your groin can produce pain, heaviness, or a burning sensation in the lower left abdomen. You might notice a visible bulge that becomes more obvious when you stand, cough, or strain, and that flattens when you lie down. The discomfort tends to worsen with activity and improve with rest.
A hernia that becomes stuck (incarcerated) or loses its blood supply (strangulated) causes sudden, severe pain and tenderness. This requires emergency treatment.
How Doctors Figure Out the Cause
The imaging your doctor orders depends on what they suspect. For women of reproductive age with pelvic pain, ultrasound is the preferred first choice because it’s excellent at evaluating ovarian cysts, ectopic pregnancies, and other reproductive causes without radiation exposure. It can also assess the urinary tract for kidney stones and even evaluate the bowel in some cases.
When diverticulitis is suspected, a CT scan is the gold standard, with 94% sensitivity and 99% specificity for confirming the diagnosis. It can also reveal complications like abscesses or perforations that change how the condition is treated.
Signs That Need Urgent Attention
Most lower left abdominal pain turns out to be something manageable, but certain patterns warrant immediate medical care. Seek emergency attention if your pain is sudden and severe, does not ease within 30 minutes, or is accompanied by continuous vomiting. A fever combined with worsening abdominal tenderness, a rigid or swollen abdomen, bloody stool, or signs of shock like dizziness and rapid heartbeat all point to conditions that can become dangerous without prompt treatment.