The spleen is part of your body’s lymphatic system. The lymphatic system helps remove cellular waste, maintain fluid balance, and make and activate infection-fighting white blood cells for the immune system. It’s also responsible for making substances that play an important role in inflammation and healing.

The spleen sits in the upper left part of your abdomen. It’s located behind your ribs, under your diaphragm, and above and behind to your stomach.

This fist-shaped, oblong organ is purple, and it weighs about 6 ounces in healthy individuals. It can become significantly larger when a person is sick or injured. Your spleen is involved in your body’s immune response, and in recycling old blood cells.

One of the spleen’s main jobs is to filter your blood. It affects the number of red blood cells that carry oxygen throughout your body, and the number of platelets, which are cells that help your blood to clot. It does this by breaking down and removing cells that are abnormal, old, or damaged.

The spleen also stores red blood cells, platelets, and infection-fighting white blood cells.

The spleen plays an important role in your immune system response. When it detects bacteria, viruses, or other germs in your blood, it produces white blood cells, called lymphocytes, to fight off these infections.

Many different conditions can cause the spleen to enlarge, especially diseases that cause blood cells to break down too quickly. An excess destruction of blood cells, for example, can overwork the spleen, and cause it to enlarge.

Other conditions that cause an enlarged spleen include:

  • bacterial, viral, and parasitic infections such as syphilis, tuberculosis, endocarditis, mononucleosis (mono), and malaria
  • blood cancers such as Hodgkin’s disease, leukemia, and lymphoma
  • liver diseases like cirrhosis
  • hemolytic anemia
  • metabolic disorders like Gaucher’s disease and Niemann-Pick disease
  • a blood clot in a vein of the spleen or liver

When your spleen enlarges, it can’t filter your blood as efficiently as it once did. It may accidentally filter out normal red blood cells and platelets, leaving fewer healthy blood cells in your body. An enlargement of the spleen that leads to the destruction of too many blood cells is a condition called hypersplenism.

An enlarged spleen may not cause symptoms at first. Eventually, it can become painful. If your spleen enlarges too much, it can rupture. The spleen can also become injured or rupture immediately after a hard hit to the abdomen, a rib fracture, or other accident. This can lead to removal of the spleen.

It’s difficult to protect the health of the spleen. Many causes of an enlarged spleen, such as cancer or blood cell abnormalities may be unavoidable. However, there are a few preventable causes of an enlarged spleen, such as avoiding infections or injuries that could damage it. Here are a few tips:

  • Don’t share personal items like silverware, toothbrushes, or drinks with other people, especially if you know they’ve been sick with an infection like mono.
  • If you play football or other contact sports, wear safety gear, including padding, to help protect your spleen and other organs from injury.
  • Use a condom every time you have sex with a new, untested partner to protect you from sexually transmitted infections.
  • If you drink alcohol, do so in moderation to protect your liver and avoid cirrhosis. (Moderate drinking means no more than one drink a day for women, and two for men.)
  • Wear your seatbelt whenever you drive or ride in a car.

If you do develop an enlarged spleen, follow the treatment plan your doctor recommends. Avoid contact sports and other high-impact activities until cleared by your doctor.

Yes, you can live without your spleen. It’s an important organ, but not essential. If it’s damaged by disease or injury, it can be removed without threatening your life. The surgery to remove your spleen is called a splenectomy.

Your lymph nodes and liver can take over many of the spleen’s important functions. Yet without your spleen, you will be more likely to get certain infections. And if you do get sick, it can take longer than usual for you to recover.

Depending on your age and overall health, your doctor will likely recommend that you get vaccinated against infections like these:

  • Haemophilus influenza type b (Hib)
  • influenza (the flu)
  • meningitis
  • tetnus, diphtheria and whooping cough (Tdap)
  • shingles
  • chicken pox
  • HPV (human papilloma virus)
  • measles, mumps and rubella (MMR)
  • pneumonia

Though your spleen isn’t a large organ, it plays many important roles in your body. It helps remove old and damaged blood cells, and it produces infection-fighting cells to protect your health. The spleen also makes certain substances that have an important role in inflammation and healing.

Infections and injuries can damage your spleen and cause it to enlarge or even rupture. If the damage is extensive, you might need surgery to remove your spleen. You can live a normal, healthy life without a spleen. But you’ll need to take extra precautions to prevent infections.