The left side under the ribs contains several important organs, including the heart, left lung, pancreas, spleen, stomach, and left kidney. Pain in this area can be caused by injury, infection, or an underlying condition. Some possible causes of pain under the left ribs include:

• Injury or inflammation to organs: Infection, inflammation, or injury to any of the organs in this area can cause pain to radiate under and around your left rib cage. It’s also possible to injure your ribs themselves.

• Enlarged spleen: The spleen is an organ that sits just below your left rib cage. Many conditions, including infections, liver disease, and some cancers, can cause an enlarged spleen. Symptoms of an enlarged spleen include pain or fullness in the left upper belly that can spread to the left shoulder, feeling full without eating or after eating a small amount, low red blood cells (anemia), frequent infections, and bleeding easily.

• Heart attack: Although the heart is not located in the left upper abdomen, conditions that affect the heart can cause pain in this area. Pain in the upper left abdomen under your ribs can be a heart attack symptom, and if you suspect you may be having a heart attack or another medical emergency, call 911 or your local emergency number immediately.

If you experience pain in your left upper abdomen under your ribs, especially if its severe or the pain gets worse when you take a deep breath, you should see a doctor promptly.