Pain in your lower left abdomen usually involves the sigmoid colon, the S-shaped section of your large intestine that sits just above your left hip. In women, the left ovary and fallopian tube also occupy this area. The cause ranges from something as temporary as trapped gas or a pulled muscle to conditions that need medical attention, like diverticulitis or kidney stones. What matters most is the type of pain, how long it’s lasted, and what other symptoms came with it.
Diverticulitis: The Most Common Cause in Adults
Diverticulitis is the single most likely diagnosis when a doctor evaluates lower left abdominal pain, especially in adults over 40. Small pouches form along the wall of the sigmoid colon over time, and when one of those pouches becomes inflamed or infected, the result is a steady, aching pain in the lower left side that can last for days. Fever and a general feeling of being unwell often accompany the pain. You might also notice changes in bowel habits, nausea, or pain that worsens after eating.
A CT scan is the preferred test for confirming diverticulitis. It reveals the extent of inflammation and rules out complications like abscesses or perforations. In mild, uncomplicated cases where you’re otherwise feeling well and don’t have a high fever, current guidelines from the UK’s National Institute for Health and Care Excellence suggest that antibiotics may not even be necessary. Rest, a temporary liquid diet, and pain management are often enough. More severe episodes, particularly if you have a fever, a weakened immune system, or other health conditions, typically require antibiotics and closer monitoring.
Irritable Bowel Syndrome
If your lower left pain keeps returning over weeks or months, especially alongside bloating, diarrhea, constipation, or both, irritable bowel syndrome (IBS) is a strong possibility. IBS is diagnosed when you’ve had recurring abdominal pain at least one day per week for the last three months, with symptoms first appearing at least six months before that. The pain tends to improve or worsen around bowel movements.
IBS doesn’t cause visible damage to the colon, which is why imaging and blood tests come back normal. That’s actually part of how it’s identified: ruling out other conditions first. The lower left side is a common location because the sigmoid colon is the narrowest, most muscular part of the large intestine and tends to spasm under stress or after certain foods.
Left-Sided Ulcerative Colitis
Ulcerative colitis is an inflammatory bowel disease where the immune system attacks the lining of the colon. There’s a specific subtype called left-sided colitis, where inflammation extends from the rectum up through the sigmoid and descending colon. Symptoms include bloody diarrhea, cramping pain on the left side, and a frustrating feeling of needing to have a bowel movement but being unable to, known as tenesmus.
Unlike IBS, ulcerative colitis causes visible inflammation and ulcers that show up during a colonoscopy. Symptoms tend to develop gradually over weeks rather than appearing suddenly. If you’re having persistent left-sided pain along with blood in your stool, ongoing diarrhea that doesn’t respond to over-the-counter medications, or diarrhea that wakes you at night, those are patterns worth getting evaluated.
Kidney Stones
A stone that forms in the left kidney and moves into the ureter (the tube connecting the kidney to the bladder) can produce intense pain in the lower left abdomen, side, or groin. Kidney stone pain is distinctive: it comes in severe waves, builds to a peak, then eases before returning. You might also notice blood in your urine, painful urination, or nausea. The pain often shifts location as the stone travels downward through the ureter toward the bladder.
Small stones frequently pass on their own within a few days to a couple of weeks, though the process can be very uncomfortable. Larger stones sometimes require medical procedures to break them up or remove them.
Causes Specific to Women
Because the left ovary and fallopian tube sit in the lower left quadrant, several gynecologic conditions can produce pain in this exact spot.
Ovarian cysts are fluid-filled sacs that develop on or inside the ovary. Most are harmless and resolve without treatment during a normal menstrual cycle, but larger cysts can cause a dull ache or sharp pain, especially if they twist or rupture. A ruptured cyst often produces sudden, intense pain that may come with light bleeding.
Endometriosis occurs when tissue similar to the uterine lining grows outside the uterus. It can attach to the ovary, bowel, or pelvic lining and cause chronic pain that often worsens around your period. Some people experience pain during sex or bowel movements as well.
Ectopic pregnancy, where a fertilized egg implants in the fallopian tube instead of the uterus, is a medical emergency. If you’re of childbearing age and have sudden, sharp lower abdominal pain along with missed periods, vaginal bleeding, or dizziness, this needs immediate evaluation. For women of childbearing age, pelvic ultrasound is the preferred first imaging test to quickly assess for gynecologic causes, including ectopic pregnancy.
Inguinal Hernia
A hernia happens when part of the intestine pushes through a weak spot in the abdominal wall, usually near the groin. The telltale sign is a visible or palpable bulge that becomes more obvious when you stand up, cough, or strain. You might feel a burning or aching sensation at the bulge, along with pressure or discomfort that gets worse when bending over, lifting, or coughing. In men, the protruding tissue can descend into the scrotum, causing pain and swelling around the testicles.
Hernias don’t heal on their own and generally require surgical repair, though the timing depends on how symptomatic it is. A hernia that suddenly becomes very painful, firm, or can’t be pushed back in is an emergency because the trapped intestine may lose its blood supply.
Constipation and Trapped Gas
Before assuming the worst, it’s worth noting that the sigmoid colon is a common site for stool to accumulate and gas to get trapped. Constipation can produce a surprisingly sharp, crampy pain in the lower left side that resolves once you have a bowel movement. If you haven’t been drinking enough water, have recently changed your diet, or are taking a new medication, constipation is a likely explanation for mild, intermittent pain without other symptoms.
When Lower Left Pain Needs Urgent Attention
Certain symptoms alongside lower left abdominal pain signal that something serious may be happening. Get to an emergency room or call your doctor promptly if you experience any of the following:
- Severe pain that doesn’t let up or keeps getting worse
- Fever or chills
- Blood in your stool or urine
- Vomiting blood
- Inability to pass gas or have a bowel movement (this can indicate a bowel obstruction)
- Yellowing of your skin or eyes
- Shortness of breath
- Mild pain that has gradually worsened over days or weeks
Even without these red flags, pain that keeps coming back deserves a conversation with your doctor. A physical exam, basic blood work, and sometimes a CT scan or ultrasound can usually narrow down the cause and point you toward the right treatment.