Understanding the Spleen: Your Body’s Natural Filter and Defense Shield
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer
The spleen is a fist-sized organ inside your left rib cage, above the stomach. [1] It filters your blood, removing old or damaged cells and waste, stores healthy blood, and makes white blood cells and antibodies that fight infection. [1] It also helps maintain the body’s fluid levels. [1] You can live without a spleen, but with a higher risk of serious infections. [1]
What the research says
Mononucleosis can make the spleen rupture, usually within the first three weeks. A systematic review of 171 articles documented 186 cases of splenic rupture in Epstein-Barr virus mononucleosis. About 80% occurred within three weeks of symptom onset, only 9.1% followed trauma, and mortality was 4.8%. (Toti et al., Swiss Medical Weekly, 2023) [2]
Having no spleen raises the risk of severe COVID-19 requiring hospital care. A meta-analysis of 4 studies found splenectomy or asplenia was linked to more severe COVID-19 outcomes overall (OR 1.92, 95% CI 1.06–3.47) and to hospitalization (OR 2.06, 95% CI 1.21–3.49). The link with death was not statistically significant. (Bianchi et al., Vaccines, 2025) [3]
In children, most spleen injuries heal without surgery. Across 67 studies of 37,340 children with abdominal solid organ injuries (spleen, kidney and liver), non-operative management failed in about 4% (pooled prevalence 0.04, 95% CI 0.03–0.06). Failure was more likely with higher injury severity and older age. (Gamberini et al., Injury, 2025) [4]
The Role and Function of the Spleen
The spleen is a multi-purpose hub of the lymphatic system. [1] Its main job is to filter the blood continuously, finding and removing waste, debris and old or damaged blood cells so that healthy cells stay in circulation. [1]
It is also a blood reservoir that can release stored blood into circulation during stress or injury, and it makes the white blood cells and antibodies that identify and neutralize bacteria and viruses.
Function | Description | Primary goal |
Blood filtration | Removes cellular waste and old or damaged red blood cells from circulation | Quality control |
Immune support | Makes white blood cells and antibodies to fight pathogens | Infection defense |
Blood storage | Holds a reserve of blood for times of physical stress | Emergency supply |
Fluid balance | Helps maintain the body’s fluid levels | Homeostasis |
Anatomy of the Spleen: Red and White Pulp
Inside, the spleen has two kinds of tissue called pulp. [1] The white pulp handles immune surveillance, holding clusters of white blood cells that watch the blood for invaders and make antibodies. The red pulp makes up most of the organ’s volume and does the filtering, using venous sinuses and splenic cords to strain the blood, destroy old cells and trap bacteria and viruses.
Tissue | Main component | Key responsibility |
White pulp | White blood cells (lymphocytes) | Antibody production and immune defense |
Red pulp | Venous sinuses and splenic cords | Blood filtration and waste removal |
Common Disorders and Impact on Health
An enlarged spleen (splenomegaly) is one of the most common findings. It can result from blood cancers such as leukemia and lymphoma, liver disease such as cirrhosis, and infections such as mononucleosis and malaria. [1] An enlarged spleen is more likely to rupture, which can cause life-threatening internal bleeding. [1]
Functional asplenia means the spleen is still present but does not do its job, which can occur in conditions such as sickle cell disease and celiac disease. [1] In hypersplenism, an overactive spleen destroys healthy blood cells too early, leading to anemia or a higher risk of infection.
Condition | What happens | Possible effects |
Splenomegaly | The spleen becomes enlarged | Fullness after small meals, higher rupture risk |
Ruptured spleen | The spleen tears, usually after trauma | Left-sided pain under the ribs, fast heartbeat, dizziness, nausea |
Functional asplenia | The spleen is present but not working | Higher risk of serious infection |
Hypersplenism | An overactive spleen removes blood cells too early | Anemia and infection risk |
Splenectomy | The spleen is surgically removed | Lifelong infection-prevention measures |
Warning signs
Pillars of Spleen Health and Maintenance
The spleen works closely with the lymphatic and immune systems, so overall wellness supports it. For people who have had a splenectomy, care shifts toward infection prevention, because the spleen is a major source of antibodies. That means staying current on vaccinations, including the pneumococcal vaccine, and in some cases taking daily antibiotics.
Health Care Pillars
Hydration and nutrition: drink plenty of water and eat a balanced diet rich in fruits and vegetables. [1]
Regular exercise: physical activity supports healthy circulation.
Infection prevention: keep vaccinations up to date, especially if your spleen is missing or damaged, and ask your provider whether daily antibiotics are right for you. [1]
Healthy weight: maintaining a healthy weight supports overall health. [1]
Injury protection: because trauma such as a car accident is a leading cause of rupture, [1] wear seat belts and protective gear.
Conclusion
The spleen is both a quiet guardian of your bloodstream and a key architect of your immune response. By filtering waste and preparing the body to fight infection, it keeps your internal environment balanced. Knowing the risks of spleen disorders and keeping up healthy habits and vaccinations helps protect this vital organ, or protect you if you live without it.
When to see a healthcare professional
If you have pain under your left rib cage, unexplained bruising or bleeding, or frequent fullness after small meals, contact a healthcare professional. Severe left-sided abdominal pain after an injury needs emergency care. Early detection of spleen problems can prevent serious complications.
Frequently Asked Questions
1. Where exactly is the spleen located?
In the upper left abdomen, inside the left rib cage and just above the stomach.
2. How big is a healthy spleen?
In most adults it is about the size of a fist or an avocado.
3. Can you live without a spleen?
Yes. The liver and other lymphatic tissue take over many of its filtering functions, but the risk of serious infection is higher.
4. What is the most common cause of a ruptured spleen?
Physical trauma, such as a car accident or a significant blow to the abdomen.
5. What is splenomegaly?
The medical term for an enlarged spleen, which can be caused by infections, liver disease or certain cancers.
6. Why does an enlarged spleen make you feel full quickly?
The spleen sits just above the stomach, and when it grows it can press on the stomach, causing early satiety.
7. What is a splenectomy?
The surgical removal of the spleen, usually because of severe injury or disease.
8. What are the risks of not having a spleen?
The main risk is a higher susceptibility to serious bacterial and viral infections.
9. How does the spleen help with fluid balance?
The spleen works with the lymphatic system to help maintain the body’s fluid levels.
10. What is the difference between red pulp and white pulp?
White pulp drives immune responses and antibody production, while red pulp filters and cleans the blood.
11. Does the spleen produce red blood cells?
In adults it mainly filters them, but it can produce them in some disease states and before birth.
12. What infections commonly cause spleen swelling?
Mononucleosis is a common cause, along with malaria, syphilis and endocarditis.
13. Can celiac disease affect the spleen?
Yes. Celiac disease is one of the conditions that can lead to functional asplenia, where the spleen stops working properly.
14. Are there specific foods that help the spleen?
No single food is proven to help. A balanced diet with plenty of fruits and vegetables supports overall health, including your immune system.
15. Should people without a spleen take daily antibiotics?
Some healthcare providers recommend it, particularly for people with other immune-compromising conditions. Ask your provider what is right for you.
Related Reading
Enlarged Spleen: Symptoms, Causes, and Treatment explains why the spleen swells and how the cause is found.
What Is a Ruptured Spleen? A Plain-Language Guide to the Injury That Can Turn Serious Fast covers the warning signs and emergency treatment of a ruptured spleen.
Splenectomy: Procedure, Recovery, and Long-Term Care describes surgery to remove the spleen and recovery afterward.
What Is Asplenia? Living Safely Without a Working Spleen explains infection risks and vaccines for people without a working spleen.
References
Cleveland Clinic. Spleen: Function, Location & Size, Possible Problems. Cleveland Clinic. Last updated April 29, 2021. https://my.clevelandclinic.org/health/body/21567-spleen
Toti JMA, Gatti B, Hunjan I, et al. Splenic rupture or infarction associated with Epstein-Barr virus infectious mononucleosis: a systematic literature review. Swiss Med Wkly. 2023;153:40081. PMID 37245117. https://doi.org/10.57187/smw.2023.40081
Bianchi FP, Giotta M, Martinelli A, et al. Assessing the vulnerability of splenectomized patients to severe COVID-19 outcomes: a systematic review and meta-analysis. Vaccines (Basel). 2025;13(2):203. PMID 40006749. https://doi.org/10.3390/vaccines13020203
Gamberini L, Moro F, Cavagna S, et al. Prevalence of non-operative management failure in pediatric patients with traumatic abdominal solid organ injuries: a systematic review and meta-analysis. Injury. 2025;56(8):112592. PMID 40683059. https://doi.org/10.1016/j.injury.2025.112592
Medical disclaimer
The information provided in this article is for educational purposes only and is not intended as medical advice. Always seek the guidance of a qualified healthcare professional regarding any medical condition or treatment.
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