Types of Drainage From a Surgical Wound

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Portrait of surgical nurse wearing surgical cap and mask in operating theater
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If you or a loved one has had surgery recently, you may be concerned about the surgical incision site—how to care for it, what it looks like, and if it appears to be healing properly. One thing to be aware of is drainage from the site, known as exudate. While it can be alarming to see drainage from a surgical wound, usually it's perfectly normal and even expected.

That said, in some cases, drainage can be a sign of infection—something that's fairly easy to prevent by taking simple steps like proper handwashing. Keeping an eye out for early signs of infection is also important, as the earlier infection is identified the faster it can be treated, which reduces healing time.

Normal vs. Abnormal Wound Drainage

Exudate 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 evaluate if you should alert your healthcare provider that something is wrong.

Normal Wound Drainage
  • Exudate is clear or slightly yellow, or tinged with pink

  • Fluid is thin and watery; may cause dressing to be damp

  • Drainage has no odor

  • A very small amount of bleeding

  • Swelling, redness, tenderness diminish with time

Abnormal Wound Drainage
  • Exudate contains large amounts of blood

  • Drainage contains pus and is yellow, grey, green, pink, or brown

  • Drainage smells foul, even if it's clear

  • Blood is gushing from wound

  • Wound becomes increasingly red, tender, and swollen

Types of Normal Wound Drainage

Here's a closer look at the various types of normal exudate.

Serous Exudate

This type of fluid is normal from a wound in the early stages of healing, typically in the first 48 to 72 hours after the incision is made. While serous fluid is normal in small amounts, experiencing large amounts of clear fluid leaving your incision warrants a call to your surgeon.

In some cases, serous fluid can actually weep from the skin, even where there is no trauma or incision. This typically happens in response to severe pitting edema due to a medical condition or after massive amounts of fluid are given, such as during treatment for severe trauma.

Serosanguinous Drainage

This thin, watery drainage is composed of both blood and serum and may appear slightly pink from the small number of red blood cells that are present. This discharge is normal in the early stages of healing, as the blood is present in small amounts. A very small percentage of blood in the fluid can make serum appear pink.

Types of Abnormal Wound Drainage

These descriptions of exudate that indicate there may be a problem with how a surgical wound is healing can help you know if you should see your surgeon.

Bloody/Sanguineous Drainage

This is abnormal wound drainage that typically has a larger amount of blood present than in serosanguinous drainage. This bloody drainage is not typical of a healing wound.

It may indicate that the wound hasn't been treated gently enough during incision care, the patient is being too active too quickly after surgery, or another type of stress is affecting the incision site. Report this type of drainage to your surgeon.

Mostly/All Blood

Hemorrhage is the term for severe bleeding from a wound. It can be life-threatening, depending on the amount of blood loss, how difficult the bleeding is to control, how long the bleeding goes unchecked, and other injuries.

The term hemorrhage refers specifically to blood being lost at a rapid rate. Medical attention is an absolute necessity for treating hemorrhages and may include blood transfusions and fluid resuscitation. In terms of drainage, hemorrhage is pure blood or nearly all blood. Seek treatment immediately.

Colorful Drainage

Purulent drainage, better known as pus, is not a normal finding in an incision. This type of drainage can be a variety of colors, including white, yellow, grey, green, pink, and brown.

Assume that this type of drainage is a sign of infection until proven otherwise. Color alone does not indicate infection, but a change from clear drainage to colorful drainage should be reported to the surgeon.

Foul-Smelling Drainage

In addition to being a variety of colors, purulent (pus) discharge may also have unpleasant or foul smells. While this smell is not always present, it is typical of this type of infection.

Foul-smelling discharge should not be ignored as it is never considered normal. Clear discharge with a foul odor should be considered a sign of infection until proven otherwise.

Amount of Wound Drainage

While the type of drainage is important, the amount of drainage may be more important, depending upon the type. For example, if there is a small amount of bleeding from a wound, it may not be alarming, but blood gushing from a wound, known as a hemorrhage, is a life-threatening condition.

In general, the amount of discharge and the amount of blood in the discharge should decrease in the days following surgery. More discharge is expected in the first few days following surgery.

After that, most wounds will typically have less discharge with less blood in it until there is no discharge whatsoever and the wound has completely closed.

A Word From Verywell

It can be a nerve-wracking thing, having a surgical wound, but that doesn't mean there is something to worry about. Normal wounds have normal drainage—it's clear or there is a little bit of blood or color—and it seems to get better day after day, or at least week after week.

Abnormal wounds look angry and have angry drainage. They get worse—more tender, more drainage, more swelling—and they also feel worse most of the time.

Sometimes these angry wounds get worse quite quickly, and when that happens there is no denying the need for medical intervention. Trust your instincts and call your medical provider in this case.

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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. Michigan Medicine. University of Michigan. Incision Care After Surgery. Updated December 13, 2018.

  2. Identifying the Different Types of Wound Drainage. WoundSource.

  3. Wounds with Heavy or Purulent Drainage. WoundSource.

Additional Reading
  • Advance For NPs and PAs. Wound Exudate: An Influential Factor In Healing.