Types of Drainage From a Surgical Wound

Learn what's normal and abnormal, and what to look for

It is normal to experience the drainage of fluid from a wound at an incision site after surgery. The drainage, which tends to be thin and slightly pink in color, may last for a few days or longer depending on how deep or extensive the wound is.

However, there are times when the drainage—known as exudate—may seem abnormal either in its duration, consistency, color, or smell. These could be signs of slow healing, an infection, or an injury to a vein or artery. Knowing the difference can help you know when it's time to seek medical care.

This article looks at six different types of wound drainage that can occur after surgery, including what is normal and what is not. It also explains when to see a healthcare provider if there are signs of an infection or injury.

Portrait of surgical nurse wearing surgical cap and mask in operating theater
Caiaimage/Martin Barraud / Getty Images

Types of Normal Wound Drainage

When you undergo surgery, it is normal to experience drainage from the wound. There may be some short-term bleeding, but that tends to resolve quickly and be followed by a thin fluid discharge. The discharge may be clear or slightly pinkish in color depending on how many tiny blood vessels, called capillaries, are damaged.

The color and consistency of the drainage can vary based on which component of blood is leaking from the wound. These include:

  • Plasma: This is the largest component of blood that is light yellow in color and transports blood cells throughout the body.
  • Red blood cells: Also known as erythrocytes, these cells give blood its red color.
  • White blood cells: Also known as leukocytes, these cells help fight infection and disease.
  • Platelets: Also known as thrombocytes, these cells help blood clot to stop bleeding.

With normal wound drainage, plasma will be the main fluid seeping from the wound. Even so, there may variations in the amounts and color of the fluid drainage.

There are two types of wound drainage that are considered normal.

Serous Drainage

Plasma is composed primarily of serum, a fluid consisting mostly of water, and proteins called fibrinogens that work with platelets to help your blood clot. Serum is also known as serous fluid or serous exudate.

Serous drainage means that the fluid seeping from a wound is thin and watery with a slightly yellowish hue. There may be crusting around the wound due to the clumping of fibrinogens.

Serous drainage typically occurs in the first 48 to 72 hours of surgery. It may be accompanied by redness, swelling, and warmth around the incision, which is a normal inflammatory response that helps aid with healing.

Serosaguineous Drainage

Serosanguineous drainage is a thin, watery discharge made up of serum and a small amount of red blood cells. The discharge may be pinkish or even have a few visible clots or blood streaks. The drainage should become clearer as the healing process begins.

Serosanguinous drainage—sero meaning "serum" and sanguine meaning "blood"—is more likely if a surgical wound is deep but can also occur if you have a low platelet count.

When to Call a Healthcare Provider

While serous or serosanguineous drainage is normal in small amounts, call your surgeon or healthcare provider if the drainage is profuse or persists for longer than 72 hours.

Types of Abnormal Wound Drainage

With proper wound care, drainage from an incision should resolve without incident. There are times, however, when an infection or injury can cause abnormal wound healing.

If the drainage from a wound seems in any way abnormal, contact your surgeon or healthcare provider without delay. In some cases, you may need to seek emergency care.

There are four types of wound drainage that are considered abnormal.

Sanguineous Drainage

Sanguineous drainage is when thicker red blood is draining from the wound. It can occur when there is a deep incision through multiple layers of tissues. It can also occur if a larger blood vessel is accidentally cut or knicked or you overexert yourself before the wound has sufficiently healed.

Sanguineous drainage usually happens soon after surgery and may resolve on its own once there is ample clotting. Even so, it is never considered normal and should be seen by a healthcare provider immediately.

Hemorrhagic Drainage

Hemorrhagic drainage is when blood is freely flowing from a wound. It usually occurs when an artery or vein has been damaged.

If the blood is bright red and spurts or gushes, it means that an artery has been ruptured. If the blood is dark red and steadily flowing, it means that a vein has been ruptured.

Hemorrhagic drainage can be life-threatening depending on the amount of blood lost, how difficult the bleeding is to control, and how long the bleeding has gone unchecked.

Emergency care is an absolute necessity. Surgery, blood transfusions, and intravenous (IV) fluids may be needed to stop the bleeding and avoid severe complications, including shock and death.

Purulent Drainage

Purulent drainage involves the presence of pus. Pus is a thick fluid made up of dead cells, tissues, and bacteria that can develop when there is an infection. Pus often has a foul smell and can be many different colors, including white, yellow, gray, green, or brown.

With purulent drainage, there may be other signs of infection including fever, chills, and increasing redness, pain, and swelling on or around the incision site. There may even be wound dehiscence (in which the incision starts to open up).

Purulent drainage needs to be seen by a healthcare provider as a matter of urgency to avoid complications like cellulitis and sepsis. The treatment may involve oral, topical, and/or IV antibiotics depending on the severity of the infection.

Seropurulent Drainage

Seropurulent drainage means that serum and pus have mixed together to form a milky, white discharge. The discharge may have a foul smell or no smell. There may also be signs of an infection, such as fatigue, low-grade fever, and swelling, redness, and tenderness at the incision site.

Even if the infection is milder, you need to see a healthcare provider to ensure that you are given the right treatment and that the infection doesn't get worse.

When to Seek Medical Care

Drainage from a surgical wound can tell you a lot about whether the site is healing properly or not.

Here are some differences between normal and abnormal wound drainage that can help you to decide when it is time to see a healthcare provider.

Normal
  • The drainage is clear, slightly yellow, or tinged with pink.

  • The fluid discharge is thin and watery.

  • The drainage has no odor.

  • There is only a very small amount of bleeding.

  • Pain, swelling, and redness are improving.

Abnormal
  • The drainage contains large amounts of blood.

  • The drainage is milky or yellow, grey, green, or brown.

  • The drainage smells foul.

  • The is a steady flow or gushing of blood.

  • Pain, swelling, and redness are getting worse.

Summary

Normal wound drainage involves the discharge of thin, watery fluids that may be clear or contain tiny amounts of blood. Abnormal wound drainage is when the discharge is thick, bloody, or has a milky white, yellow, green, gray, or brown color (often with a foul smell).

Abnormal wound drainage should be seen by your surgeon or healthcare provider without delay. If there is significant bleeding that doesn't stop, rush to your nearest emergency room.

Frequently Asked Questions

  • Should I drain the pus out of an infected wound?

    No, you should not drain the pus yourself. It is important to get the underlying infection treated by a healthcare provider, usually with antibiotic drugs. The pus may need to be drained, but doing so yourself can push the pus into deeper tissues and make the infection worse.

  • What are the types of surgical drains?

    Two common surgical drains are chest tubes and bulb-type drains. A chest tube drains fluids that gather around the heart or between the lungs and chest wall. Bulb-type drains, such as the Jackson-Pratt (JP) drain, use a rubber bulb to draw fluid out of the body with gentle suction.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. WoundSource. Wounds with heavy or purulent drainage.

  2. WoundSource. Identifying the different types of wound drainage.

  3. Michigan Medicine. University of Michigan. Incision care after surgery.

By Jennifer Whitlock, RN, MSN, FN
Jennifer Whitlock, RN, MSN, FNP-C, is a board-certified family nurse practitioner. She has experience in primary care and hospital medicine.