The lymphatic system is a network of vessels, lymph nodes and organs that collects extra fluid from your tissues, filters it and returns it to your bloodstream. It also carries immune cells, absorbs dietary fats from your gut and helps your body defend itself against bacteria, viruses and other invaders.
What is the lymphatic system made of?
The MedlinePlus Medical Encyclopedia describes the lymph system as a network of organs, lymph nodes, lymph ducts and lymph vessels that carry lymph from tissues to the bloodstream. It is a major part of the immune system. Its main parts include:
- Lymph, the clear to white fluid that travels through the system
- Lymphatic vessels, which carry lymph through the body
- Lymph nodes, small bean-shaped filters clustered in the neck, armpits, groin, chest and abdomen
- The spleen, the largest lymphatic organ, which filters blood
- The thymus, where T cells mature
- Bone marrow, where white blood cells are made
- Tonsils, adenoids and lymphoid tissue lining the gut and airways
Cleveland Clinic notes that you have about 600 lymph nodes spread throughout your body.
What does the lymphatic system do?
The lymphatic system has a few main jobs. A review in StatPearls, hosted by the National Library of Medicine, describes them in detail.
It balances fluid in your tissues
Blood plasma constantly seeps out of tiny capillaries into the spaces around your cells. Cleveland Clinic explains that about 20 liters of plasma leave the capillaries each day, about 17 liters return directly to the bloodstream, and the remaining 3 liters are collected by lymphatic vessels as lymph. The lymphatic system then returns this fluid, along with extra proteins, to your veins.
It supports your immune system
Lymph nodes store immune cells and filter lymph, trapping material such as bacteria. MedlinePlus explains that when nodes detect bacteria, they produce more white blood cells, which can make them swell. That is why you may notice tender nodes in your neck during a cold.
It absorbs fats from your diet
Special lymphatic vessels in the small intestine, called lacteals, absorb dietary fats and fat-soluble vitamins and carry them toward the bloodstream, according to StatPearls.
It helps drain fluid from the brain
StatPearls notes that lymphatic vessels identified in the membranes around the brain help drain cerebrospinal fluid. Separately, an NIH-funded study in mice found that the space between brain cells grew by 60 percent during sleep, letting fluid flow through more quickly. Researchers call this pathway the glymphatic system.
How does lymph move without a pump?
Your heart pumps blood, but the lymphatic system has no central pump. Cleveland Clinic explains that the pulsing of nearby arteries and the squeezing of nearby muscles help push lymph along. StatPearls adds that one-way valves in the larger lymphatic vessels prevent backflow, and that skeletal muscle contraction and breathing movements create the pressure changes that move lymph forward.
Lymph eventually reaches two collecting ducts. The thoracic duct, the largest lymphatic channel, drains most of the body. The right lymphatic duct drains the right upper body, including the right arm and the right side of the head and neck.
Because movement and breathing play such a large part, everyday habits matter. Our guide to 7 daily habits that support lymphatic drainage covers practical ideas.
How can I keep my lymphatic system healthy?
Cleveland Clinic suggests a few simple steps:
| Habit | Why it helps |
|---|---|
| Drink enough water | Helps lymph move easily |
| Exercise regularly | Working muscles squeeze lymph vessels |
| Eat a nutritious diet | Supports overall health, including immunity |
| Limit contact with toxic chemicals | Includes pesticides and some cleaning products |
Some people also enjoy a daily herbal ritual. Lymphoria Lymphatic Drainage Drops combine cleavers, red clover, stillingia and prickly ash, four herbs with a long history in traditional herbalism. Research on these herbs is limited, and the drops are not intended to treat any condition. You can learn more in our guide to the drops.
When should I see a doctor about my lymph nodes?
Cleveland Clinic recommends contacting a healthcare provider if you have extreme fatigue, swollen lymph nodes, or unexplained swelling that lasts more than a few weeks or interferes with daily life. Swollen nodes are often a sign your body is fighting an infection, but persistent changes deserve a professional look.
Frequently asked questions
Where are my lymph nodes?
Lymph nodes are spread throughout the body, with clusters in the neck, armpits, groin, chest and abdomen. MedlinePlus notes that you usually cannot see or easily feel them unless they are swollen.
Is the lymphatic system part of the immune system?
Yes. MedlinePlus describes it as a major part of the immune system. Lymph nodes store and produce white blood cells that help fight infection.
What is lymph made of?
Lymph is a clear to white fluid that contains white blood cells, mostly lymphocytes. Lymph from the intestines also carries chyle, a fluid rich in fats and proteins.
Does the lymphatic system have a pump?
No. Lymph moves with help from muscle contractions, breathing, the pulsing of nearby arteries and one-way valves inside the vessels.