Pain on the left side of your stomach can come from several different organs depending on whether it’s higher up, near your ribs, or lower down, closer to your hip. The most common causes range from trapped gas and stomach inflammation to diverticulitis and kidney stones. Where exactly you feel the pain, how it behaves, and what other symptoms come with it all point toward different explanations.
What’s on Your Left Side
Your left abdomen houses different organs in its upper and lower halves, and knowing which ones sit where helps narrow down what might be causing your pain. In the upper left area, you’ll find your stomach, spleen, the main body of your pancreas, the left portion of your kidney, your adrenal gland, and a sharp bend in your colon called the splenic flexure. In the lower left, the main structures are the sigmoid colon (the last stretch of your large intestine before the rectum) and, in women, the left ovary and fallopian tube.
Pain that stays high up, near or under your ribs, usually involves the stomach, spleen, pancreas, or kidney. Pain that sits lower, between your belly button and hip bone, more often traces back to the colon or reproductive organs.
Common Causes of Upper Left Pain
Stomach Inflammation
Gastritis, or inflammation of the stomach lining, is one of the most frequent reasons for upper left discomfort. A stomach bug or viral infection can cause temporary inflammation that resolves on its own within a few days. Longer-lasting gastritis can result from overuse of anti-inflammatory painkillers, heavy alcohol use, or bacterial infection. The pain typically feels like a burning or gnawing sensation and often gets worse after eating.
Trapped Gas at the Splenic Flexure
Your colon makes a sharp turn just below your spleen, and gas traveling through your digestive tract can get stuck at this bend. This is called splenic flexure syndrome, and it causes sharp pain in the upper left abdomen that can feel alarmingly intense for something so harmless. The pain usually eases once you pass gas or have a bowel movement. People with irritable bowel syndrome or chronic bloating are more prone to it.
Pancreas Problems
Pancreatic pain shows up in the middle or upper left side of your abdomen and often radiates straight through to your back. It’s typically a constant, severe, dull ache that gets worse after meals. Pancreatitis, or inflammation of the pancreas, is the usual culprit. Gallstones and heavy alcohol use are the two leading causes. In chronic pancreatitis, ongoing inflammation damages the nerves within the pancreas itself, which means pain can persist even after the original trigger is treated. This nerve damage creates a cycle where the pancreas becomes increasingly sensitive over time.
Enlarged Spleen
Your spleen sits just under your left ribcage, and when it swells, it can cause a dull ache or fullness in that area. One telltale sign is feeling full after eating very little, because the enlarged spleen presses directly against your stomach. Infections (including mononucleosis) and liver disease are common causes. An enlarged spleen that has been injured can rupture and bleed internally, which is a medical emergency producing sudden, severe pain.
Common Causes of Lower Left Pain
Diverticulitis
Lower left abdominal pain in adults, especially those over 40, is most often related to diverticular disease. Diverticula are small pouches that form in the wall of your colon, and they almost always develop in the lower left section. Most people with these pouches never have symptoms. But when one becomes inflamed or infected, the condition is called diverticulitis, and it produces steady pain in the lower left abdomen, often alongside fever, nausea, and changes in bowel habits.
Mild, uncomplicated diverticulitis can sometimes be managed without antibiotics in otherwise healthy people, with rest and a temporary shift to easily digestible foods. Antibiotics are recommended when there are complications, other health conditions, signs of systemic infection, or significantly elevated inflammatory markers. A CT scan of the abdomen and pelvis with contrast is the standard imaging test used to confirm the diagnosis and check for complications like abscesses.
Kidney Stones
A stone forming in your left kidney may not cause any pain at all while it stays in the kidney. The trouble starts when it moves into the ureter, the narrow tube connecting your kidney to your bladder. The stone blocks urine flow, the kidney swells, and the ureter spasms around it. This produces serious, sharp pain in the side and back below the ribs that spreads down to the lower abdomen and groin. The pain comes in waves, shifting location and intensity as the stone moves. It’s often described as one of the most intense pains people experience. CT without contrast is the preferred imaging test for suspected kidney stones.
Reproductive Causes in Women
In women, lower left pain can originate from the left ovary or fallopian tube. Ovarian cysts are fluid-filled sacs that develop on the ovary, and most resolve on their own. But a large or ruptured cyst can cause sudden, sharp pain on the affected side. Endometriosis, where tissue similar to the uterine lining grows outside the uterus, can also produce chronic left-sided pelvic pain if it involves the left ovary or surrounding tissue. An ectopic pregnancy, where a fertilized egg implants in a fallopian tube instead of the uterus, causes increasingly severe one-sided pain and is a medical emergency.
How the Pain Feels Matters
The character of your pain offers useful clues. A burning or gnawing sensation that worsens with food points toward the stomach. Sharp, sudden pain that comes and goes in waves suggests a kidney stone or a ruptured cyst. Steady, constant pain with fever leans toward diverticulitis or another infection. A dull ache under the ribs paired with early fullness after eating suggests an enlarged spleen. Pain that worsens after meals and bores through to your back is characteristic of the pancreas.
Crampy pain that improves after passing gas or having a bowel movement is more likely related to the colon, whether from trapped gas, irritable bowel syndrome, or constipation. Pain that gradually builds over hours and stays in one spot, especially with fever, suggests something inflammatory that won’t resolve on its own.
When Left-Sided Pain Needs Urgent Attention
Certain combinations of symptoms signal that something more serious may be happening. Persistent pain that never seems to ease, or that gets progressively worse over hours, warrants medical evaluation. Pain paired with a high fever suggests infection or inflammation such as peritonitis, diverticulitis, or an abscess. Blood in your stool alongside abdominal pain needs prompt assessment. Yellowing of the skin or eyes (jaundice) combined with pain can indicate a problem with your liver, gallbladder, or bile ducts.
Sudden, severe pain that leaves you unable to sit still or find a comfortable position, especially after an injury to the left side, raises concern for a ruptured spleen. In women of reproductive age, severe one-sided lower pain with missed periods or vaginal bleeding could indicate an ectopic pregnancy. Both situations require emergency care.
What to Expect at a Medical Visit
If your pain brings you to a doctor, the evaluation usually starts with questions about where the pain is, when it started, what makes it better or worse, and what other symptoms you’ve noticed. For lower left pain, a CT scan of the abdomen and pelvis is the most commonly recommended imaging study, particularly when diverticulitis is suspected. For upper left pain, ultrasound may be used first to evaluate the spleen or kidney, while CT is better for assessing the pancreas or complex abdominal issues. For suspected kidney stones specifically, a CT scan without contrast is preferred because it’s highly accurate at detecting stones, while ultrasound can identify swelling from a blockage but often misses the stones themselves.
Many causes of left-sided stomach pain, like trapped gas, mild gastritis, or a passing stomach bug, resolve within hours to days with simple measures. Others, like diverticulitis or kidney stones, may need a few days to a couple of weeks to fully settle. Conditions involving the pancreas or chronic issues like endometriosis often require longer-term management plans. The location, timing, and severity of your pain are the best guides to how urgently you need to be seen.