The spleen filters your blood and also stores your red blood cells, platelets, and white blood cells. But if your spleen is removed, other parts of the lymphatic system can take over these functions.

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. A 2016 research review showed that the spleen’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 your stomach.

This fist-shaped, oblong organ is purple, and it weighs between 2.5 to 7 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.

Function

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 the infections that these cause.

The spleen is located in the upper left side of the abdomen. It can be found next to the stomach and behind the left ribs.

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:

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. The same 2016 research review above showed that 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.

Some spleen concerns, such as an enlarged spleen, can be detected through a physical exam performed by your doctor.

Your doctor may also conduct an ultrasound or computed tomography (CT) scan to assess the size of your spleen.

A blood test can also be used to evaluate your liver function or determine if you have high levels of white blood cells in your body, which could indicate an infection.

Magnetic resonance imaging (MRI) scans can also detect tumors and cysts, or can be used to monitor blood flow through the spleen.

It’s difficult to protect the health of the spleen. While many causes of an enlarged spleen, such as cancer or blood cell abnormalities may be unavoidable, the United Kingdom’s National Health Service says that there are many treatment options available for other spleen concerns, including:

  • Watchful waiting. If you aren’t currently experiencing any symptoms, your doctor may suggest waiting to see if spleen concerns resolve on their own. They may recommend reevaluating your condition in a few months, or sooner if you start experiencing symptoms.
  • Medications. Certain drugs, such as antibiotics, may be used to treat any underlying concerns that could be causing your enlarged spleen.
  • Diet and lifestyle changes. Making modifications to your diet and lifestyle may help improve certain conditions that can trigger spleen concerns, such as cirrhosis or rheumatoid arthritis. Generally, this involves eating plenty of nutrient-dense foods, limiting your intake of sodium, and getting regular physical activity.
  • Surgery. In severe cases, spleen removal may be necessary, especially if the enlarged spleen is causing serious complications or other treatment options are limited.

There are also several ways to prevent an enlarged spleen, such as by avoiding infections or injuries that could damage it. Here are a few tips to try as best you can:

  • 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 or other barrier method when having sex with a new, untested partner to protect yourself from sexually transmitted infections.
  • If you drink alcohol, do so in moderation to protect your liver and avoid cirrhosis.
  • Wear your seatbelt whenever you drive or ride in a car.

If you do develop an enlarged spleen, consider following the treatment plan your doctor recommends. Try to avoid contact sports and other high-impact activities until cleared by your doctor.

The National Health Service says 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 being life threatening. 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, the organization above also says that you will be more likely to develop certain infections. And if you do get sick, it can take longer than usual for you to recover.

The Centers for Disease Control and Prevention says that depending on your age and overall health, your doctor will likely recommend that you get these vaccines:

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.