Hemostasis is your body’s natural reaction to an injury that stops bleeding and repairs the damage. This capability is usually for your benefit, conserving blood and preventing infections. In rare cases, the process doesn't work as it should, and this can cause problems with too much or too little clotting.


During hemostasis, your body plugs a bleeding wound and uses that plug as a starting point to repair the injury.
Hemostasis is how your body plugs and repairs a wound.

What is hemostasis?

Hemostasis is your body’s normal reaction to an injury that causes bleeding. This reaction stops bleeding and allows your body to start repairs on the injury. This capability is essential to keep you alive, particularly with significant injuries. However, in uncommon cases, the processes that control hemostasis can malfunction, causing potentially serious — or even dangerous — problems with bleeding or clotting.


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How does hemostasis work?

Hemostasis combines the terms “hemo” (meaning “blood”) and “stasis” (meaning “standing still”). In this context, it’s the term for how your body stops bleeding. Rather than being just a single process, hemostasis is actually a collection of several processes. Though they look like separate processes, these all happen at the same time when your body forms a blood clot.

Primary hemostasis (platelet clotting)

Primary hemostasis is when your body forms a temporary plug to seal an injury. To accomplish that, platelets that circulate in your blood stick to the damaged tissue and activate. That activation means they can “recruit” more platelets to form a platelet “plug” to stop blood loss from the damaged area. That clot works much like a cork or bottle stopper, keeping blood in and debris or germs out. Primary hemostasis may also involve constriction (narrowing) of the damaged blood vessel, which can happen because of substances that activated platelets release.

Secondary hemostasis (coagulation cascade)

The platelet plug is the first step to stop bleeding, but it isn’t stable enough to stay in place without help. The next step, which stabilizes the plug, is secondary hemostasis. This step, sometimes called coagulation, involves molecules in your blood called “coagulation factors.” Those factors activate in sequence, the “coagulation cascade,” which amplifies clotting effects as the sequence continues. Ultimately, the coagulation cascade forms a substance called fibrin. During this step, the platelet plug acts like bricks and the fibrin acts like mortar. Together, they form a solid, stable clot.

Fibrin clot remodeling

The last stage of hemostasis is when your body remodels the existing clot into a fibrin clot. Your body does that because blood clots are a temporary patch, not a permanent solution. That removal involves a process called fibrinolysis. During fibrinolysis, your body remodels the clot into the same kind of tissue that was there before the injury.

Possible Causes

What causes hemostasis?

Your body naturally monitors itself for injuries, and when it detects one, it reacts quickly to take control of the situation. Without normal hemostasis, even minor injuries could cause dangerous blood loss. An example of this is hemophilia, a condition where hemostasis doesn't work properly and blood can't clot effectively. Any break in your skin is also a risk for germs to enter your body. Clots help reduce that risk by sealing the injury.


What potential health problems can happen with hemostasis?

Hemostasis refers to normal blood clotting in response to an injury. However, your body can also have too much clotting, known as hypercoagulability. That can cause many blood clots to form spontaneously and block normal blood flow. When blood clots form inside your blood vessels, this is known as thrombosis. When you have thrombosis that happens repeatedly, that’s a condition called thrombophilia.

Thrombophilia (hypercoagulability or too much clotting)

Hypercoagulability is when your blood clots too much or too easily. This is dangerous because those clots can develop or get stuck in different places in your body and cause severe, life-threatening problems. Examples of these problems include:

Many types of cancer can cause hypercoagulability, and some rare conditions that cause hypercoagulability are also genetic. That means they are either inherited from your parents or happen because of a random mutation in your DNA. People with these conditions have thrombophilia. A few examples of conditions like this include:

Inherited disorders that cause thrombophilia aren’t as common as “acquired” conditions, which you usually develop later in life. Examples of acquired conditions include:

Most medications that treat thrombophilia make it harder for your blood to clot in some way. Examples of these include antiplatelet, anticoagulant and fibrinolytic (fibrin-breaking or clot-busting) drugs.

Hypocoagulability (not enough clotting)

When your blood doesn’t clot well, any injury becomes a much more dangerous event. Without proper clotting, even minor injuries can cause you to lose a lot of blood. It also means you’re at greater risk for injuries to organs and blood vessels inside your body, which can then cause internal bleeding.

Certain types of cancer like leukemia can cause you to bleed too easily. That’s because they often involve a lack of platelets in your body or anti-clotting activity. Conditions that keep your blood from clotting are often genetic, also. Some examples of genetic conditions include:

Treating conditions that keep your blood from clotting usually involves medications that slow down or block your body’s anti-clotting processes, that boost your body’s ability to make platelets or that add more of certain clotting factors to your blood. You can also receive transfusions of platelets to add more if your body needs them.

How are hemostasis problems diagnosed?

A healthcare provider — such as a hematologist — can diagnose blood clotting problems based on your symptoms and blood tests that analyze the clotting-related components in a sample of your blood.


When To Call the Doctor

When should I call a doctor about problems with clotting?

Hypercoagulability can happen with a variety of different symptoms depending on where and when an abnormal clot develops. Examples of this include:

  • Brain: Stroke symptoms, including weakness or paralysis on one or both sides of your body, slurring speech, inability to move one side of your face and headache.
  • Heart: Heart attack symptoms, including chest pain, shortness of breath, weakness, fast or irregular heartbeat, heart palpitations (feeling your own heartbeat) and passing out.
  • Lungs: Pulmonary embolism symptoms, including wheezing or sudden problems breathing, pain in your chest, coughing blood, fingertips or lips that are pale or blue-tinted and passing out.
  • Deep vein thrombosis (DVT): This can often lead to pulmonary embolism. Symptoms include pain in the calf or elsewhere in the leg, as well as swelling or redness. However, blood clots in your leg can sometimes have relatively minor symptoms, and may just feel like a pulled muscle.
  • Kidneys: Blockages in your kidney can cause blood in your urine (pee), needing to pee less often and pain in your lower back on either side of your spine.

Hypocoagulability will cause you to bleed more easily. Most often, this causes the following symptoms:

  • Nosebleeds that are hard to stop.
  • Bleeding around your gums when you brush your teeth.
  • Wounds that may seep or ooze blood for a long time and take much longer to heal. However cuts in certain areas, such as the face, fingertips or scalp, can take a long time to stop bleeding because there are many more blood vessels in those areas than in other places in your body.
  • Finding bruises and you can’t remember how you got them or bruising much more easily and visibly (bruises are bigger and more colorful).

A note from Cleveland Clinic

Hemostasis is a natural part of your daily life. It helps your body protect itself from bleeding and infection, and recover from injuries big and small. Understanding how it works can help you better care for yourself. It also means you can recognize potential problems with your body’s natural recovery abilities and get help sooner rather than later.

Medically Reviewed

Last reviewed on 12/08/2021.

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