Pain under your left rib cage can come from a wide range of sources, from trapped gas in the colon to an inflamed pancreas or an enlarged spleen. The left upper area of your abdomen houses several major organs: the spleen, stomach, pancreas, left kidney, adrenal gland, and portions of the colon and liver. Pinpointing the cause depends largely on what the pain feels like, when it occurs, and what other symptoms come with it.
Trapped Gas and Splenic Flexure Syndrome
One of the most common and least dangerous causes is gas trapped in the colon, specifically at a sharp bend called the splenic flexure. This is the highest-reaching segment of the colon, sitting right beneath the left ribs, and gas naturally rises to fill it. When the area becomes distended, it produces bloating, a sense of fullness, and pain in the left upper abdomen that can feel surprisingly intense. This is sometimes called splenic flexure syndrome.
The pain tends to come and go, often worsening after meals or during periods of constipation. It can feel like pressure or cramping and usually resolves on its own or with the passage of gas. If you notice the pain is closely tied to eating, bloating, or changes in bowel habits, trapped gas is a likely culprit.
Stomach-Related Causes
The stomach sits directly beneath the left ribs, so conditions like gastritis (inflammation of the stomach lining) and peptic ulcers frequently cause pain in this area. With ulcers, the timing of pain relative to meals is a useful clue. Some people feel the pain most when the stomach is empty or at night, and it goes away briefly after eating. For others, eating makes the pain worse. A burning or gnawing sensation in the upper abdomen, sometimes accompanied by nausea, is typical of both gastritis and ulcers.
Pancreatitis
The pancreas stretches across the upper abdomen, with its tail reaching toward the left side. When the pancreas becomes inflamed, the pain often settles in the upper belly and radiates to the back or shoulders. It frequently worsens after eating, particularly fatty meals.
Acute pancreatitis comes on suddenly and ranges from mild to severe. Chronic pancreatitis produces a more constant upper belly pain. A distinguishing feature of pancreatitis is that the pain can be so intense you can’t sit still or find a comfortable position. If that describes your experience, it warrants urgent medical attention.
Enlarged Spleen
The spleen sits just under the left rib cage, and when it swells (a condition called splenomegaly), it can press on surrounding structures. An enlarged spleen often causes no symptoms at all. When it does, the most characteristic sign is pain or fullness in the left upper abdomen that may spread to the left shoulder. You might also feel full after eating very little, because the swollen spleen presses against the stomach.
A ruptured spleen is a medical emergency. If the area is tender to the touch and you also experience low blood pressure, dizziness, blurry vision, or nausea, get emergency help immediately. Splenic rupture can follow trauma, like a blow to the abdomen during sports, but it can also happen spontaneously if the spleen is already enlarged.
Costochondritis
Not all pain under the left ribs comes from organs. Costochondritis is inflammation of the cartilage connecting the ribs to the breastbone, and it most commonly affects the upper ribs on the left side. The pain is sharp, aching, or feels like pressure, and it’s worst where the rib cartilage meets the sternum. It can radiate to the arms and shoulders.
The hallmark of costochondritis is that the pain gets worse with specific movements: taking a deep breath, coughing, sneezing, or twisting the torso. It often affects more than one rib. Because it can closely mimic heart attack pain, it’s important to rule out cardiac causes first. Once confirmed, costochondritis is typically managed with rest and anti-inflammatory treatment and resolves over weeks.
Kidney Stones and Kidney Pain
The left kidney sits behind the stomach and under the rib cage, toward the back. Kidney pain is usually felt in the side (the “flank”) under the ribs, and it tends to feel deeper than muscle or stomach pain. A constant, dull ache in the back or a sharper pain in the side that comes in waves can signal a kidney stone or infection.
One way to tell kidney pain apart from other causes is location: it’s centered more toward the back and side rather than the front of the abdomen. It may also be accompanied by pain during urination, blood in the urine, or fever if an infection is present.
Pleurisy
Pleurisy is inflammation of the thin tissue layers that line the lungs and chest wall. Normally, these layers glide smoothly past each other as you breathe, lubricated by a small amount of fluid. When they become inflamed, they rub together like sandpaper, producing a sharp, stabbing pain with every breath in and out.
Left-sided pleurisy causes pain under the left ribs that is very specifically tied to breathing. The pain lessens or disappears when you hold your breath, and it worsens when you cough or sneeze. This breathing-dependent pattern sets pleurisy apart from most other causes on this list. Intense chest pain during breathing should always be evaluated by a doctor.
How Doctors Identify the Cause
Because so many different organs and structures sit in this area, imaging plays a central role in diagnosis. A CT scan is currently the primary tool used to evaluate acute left upper quadrant pain in an emergency setting, as it can visualize the spleen, pancreas, kidneys, and colon in detail. Ultrasound is also commonly used, particularly for evaluating the spleen and kidneys. Your doctor will choose the approach based on your symptoms, the suspected cause, and whether the situation is urgent.
Beyond imaging, the pattern of your pain provides important diagnostic clues. Pain that worsens after eating points toward the stomach or pancreas. Pain that flares with breathing suggests pleurisy or costochondritis. Deep flank pain radiating to the back may involve the kidney. And a dull fullness that makes you lose your appetite could indicate the spleen.
Signs That Need Emergency Attention
Most causes of left-sided rib pain are not emergencies, but some are. Heart attack symptoms can include pain, discomfort, or heaviness in the chest (often on the left side), along with pain spreading to the neck, jaw, shoulders, arms, or back. Shortness of breath, sweating, nausea, lightheadedness, and a fast or irregular heart rate are additional warning signs. If you experience this combination, call emergency services immediately.
Other situations requiring urgent care include pain so severe you cannot find a comfortable position (possible pancreatitis), signs of a ruptured spleen (tenderness, dizziness, low blood pressure, blurry vision), and difficulty breathing after a rib injury, which could indicate a broken rib or collapsed lung.