Pain on the left side of your abdomen can come from several different organs depending on whether it’s higher up (near your ribs) or lower down (near your hip). The most common causes range from trapped gas and indigestion to conditions like diverticulitis, kidney stones, or irritable bowel syndrome. Where exactly the pain sits, how it feels, and what else is happening in your body all help narrow down what’s going on.
What’s on the Left Side of Your Abdomen
Your left side houses more organs than most people realize. The upper left area contains your stomach, the tail of your pancreas, and your spleen. Your left kidney sits toward the back. Running through both the upper and lower left portions are loops of your small intestine and the descending portion of your large intestine (colon), which curves down the left side before connecting to your rectum. In women, the left ovary and fallopian tube also sit in the lower left area.
Because so many structures overlap, the location and quality of the pain matter. A burning sensation high up after eating points toward different causes than a sharp, cramping pain low down. Dull, achy, sharp, crampy, twisting, or pulsing sensations each suggest different things.
Upper Left Pain: Stomach, Pancreas, and Spleen
The most common reason for upper left abdominal pain is straightforward indigestion. If you feel a burning or gnawing sensation after meals, stomach acid irritating your stomach lining is the likely culprit. This is especially true if the pain sits just below your breastbone or slightly to the left. Gastritis, acid reflux, and stomach ulcers all produce pain in this zone.
Pancreatitis causes a more intense, steady pain in the upper abdomen that often radiates to your back or shoulders and gets worse after eating. Acute pancreatitis tends to come on suddenly with nausea, vomiting, fever, and a fast heartbeat. Chronic pancreatitis produces ongoing upper belly pain along with unintentional weight loss, diarrhea, and oily stools. Gallstones and heavy alcohol use are the two most common triggers.
Your spleen, tucked under your ribs on the far left, can cause pain when it becomes enlarged. Infections, liver disease, and certain blood disorders can all swell the spleen, creating a feeling of fullness or tenderness under the left rib cage.
Lower Left Pain: Diverticulitis
Pain specifically in your lower left abdomen is most often related to diverticulitis. Small pouches called diverticula can form along the wall of your colon, and they tend to develop in the sigmoid colon, the S-shaped segment that begins on your lower left side. When one or more of these pouches become inflamed or infected, the result is diverticulitis.
The pain is often severe and constant rather than coming and going. You might also notice a swollen or tender belly, fever, nausea, constipation, or occasionally rectal bleeding. Diverticulitis becomes more common with age, and most people who have diverticula never develop symptoms. But when inflammation does set in, you’ll typically know something is wrong.
Mild, uncomplicated cases in otherwise healthy people don’t always require antibiotics. Rest and a temporary shift to easy-to-digest foods may be enough. However, if you’re running a fever, can’t keep food down, or have other health conditions, antibiotic treatment is standard. A CT scan is the go-to imaging test, with a sensitivity above 95% for confirming diverticulitis and showing whether an abscess has formed.
Gas and Irritable Bowel Syndrome
Trapped gas is one of the most common, and most underestimated, causes of left-sided abdominal pain. The descending colon runs straight down your left side, and the sharp bend where it turns (called the splenic flexure, near the spleen) is a natural spot for gas to get stuck. The result can be surprisingly sharp pain under the left ribs that mimics something more serious.
Irritable bowel syndrome frequently causes pain low on the left side or below the navel. The pain tends to follow meals, comes with an urge to have a bowel movement, and often improves after you go. IBS is driven by heightened sensitivity in the intestines, where normal digestion triggers crampy discomfort that wouldn’t bother someone without the condition. Bloating, alternating constipation and diarrhea, and pain that waxes and wanes over weeks or months are hallmarks. If your pain fits this pattern and you don’t have fever, weight loss, or bleeding, IBS is a strong possibility.
Kidney Stones
A stone moving through your left kidney or ureter produces pain that most people describe as severe and wave-like. It typically starts in your side or back, just below the ribs, then radiates forward and downward toward the groin. Men sometimes feel it in the testicles. The pain comes and goes in intense surges rather than staying constant, and it’s often accompanied by nausea, blood-tinged urine, or a frequent urge to urinate. If you’ve never experienced a kidney stone before, the intensity can be alarming, but the wave-like pattern is a useful clue that sets it apart from other causes.
Reproductive Causes in Women
For women, the left ovary and fallopian tube add another layer of possibilities. Ovarian cysts can cause a dull ache or sudden sharp pain in the lower left abdomen, especially if a cyst ruptures or twists. Mittelschmerz, a brief pain during ovulation, can also show up on the left side during months when the left ovary releases an egg.
An ectopic pregnancy, where a fertilized egg implants outside the uterus (usually in a fallopian tube), is a more serious concern. Early signs include light vaginal bleeding and pelvic pain. If the tube ruptures, symptoms escalate quickly to severe abdominal pain, extreme lightheadedness, fainting, and sometimes shoulder pain caused by internal bleeding irritating the diaphragm. This is a medical emergency. Any combination of a missed period, pelvic pain, and vaginal bleeding warrants immediate evaluation.
When Left-Sided Pain Is an Emergency
Most left-sided abdominal pain resolves on its own or turns out to be something manageable. But certain signs mean you should seek help right away:
- Severe pain with a rigid or distended abdomen, which can signal a perforation or serious infection
- Signs of gastrointestinal bleeding, such as vomiting blood or dark, tarry stools
- Fainting, extreme lightheadedness, or signs of shock, which may point to internal bleeding
- High fever with worsening pain, suggesting an infection that needs treatment
- Severe pain during pregnancy, particularly with vaginal bleeding
It’s also worth noting that heart problems can occasionally disguise themselves as upper abdominal pain, especially with nausea or unusual fatigue. This is more relevant for people over 50 or those with known heart disease.
Figuring Out What’s Causing Your Pain
Start by pinpointing the location as precisely as you can. Upper and near the center after meals points toward your stomach. Upper left with back radiation and vomiting suggests the pancreas. Lower left with fever and tenderness leans toward diverticulitis. Waves of severe pain from back to groin suggest a kidney stone. Crampy pain that improves after a bowel movement fits IBS or gas.
If the pain is new, severe, or accompanied by fever, bleeding, or vomiting, imaging will likely be part of the workup. CT scans are the first choice for lower left abdominal pain because they can identify diverticulitis, abscesses, kidney stones, and other structural problems with high accuracy. Ultrasound is useful for evaluating reproductive organs and the kidneys, though it’s less reliable than CT for conditions like diverticulitis.
Mild, intermittent pain without alarming symptoms often responds to simple measures: avoiding trigger foods, managing stress, staying hydrated, and paying attention to your bowel habits. Keeping a brief log of when the pain occurs, what you ate, and what makes it better or worse gives you useful information to share if you do end up seeing a provider.