Penile discharge is any substance that comes out of the penis that’s neither urine nor semen. This discharge usually comes out of the urethra, which runs through the penis and exits at the head. It might be white and thick or clear and watery, depending on the underlying cause.

While penile discharge is a common symptom of many sexually transmitted diseases (STDs), including gonorrhea and chlamydia, other things can cause it as well. Most of them aren’t serious, but they do usually require medical treatment.

Read on to learn about what might be causing your discharge and how to be completely sure it’s not a sign of an STD.

People usually associate urinary tract infections (UTIs) with females, but males can get them, too. There are different types of UTIs, depending on where the infection is.

In males, a type of UTI called urethritis can cause discharge.

Urethritis refers to inflammation of the urethra. Gonococcal urethritis refers to urethritis that’s caused by gonorrhea, an STD. Non-gonococcal urethritis (NGU), on the other hand, refers to all other types of urethritis.

In addition to discharge, NGU can cause:

  • pain
  • burning when urinating
  • frequent urge to urinate
  • itching
  • tenderness

An STD other than gonorrhea may cause NGU. But other infections, irritation, or injuries can also cause it.

Some potential non-STD causes of NGU include:

  • adenovirus, a virus that can cause gastroenteritis, pinkeye, and sore throat
  • bacterial infection
  • irritation from a product, such as soap, deodorant, or detergent
  • damage to the urethra from a catheter
  • damage to the urethra from intercourse or masturbation
  • genital injuries

The prostate is a walnut-shaped gland that surrounds the urethra. It’s responsible for making prostatic fluid, a component of semen.

Prostatitis refers to inflammation of this gland. The inflammation may be the result of an infection in or injury to the prostate. In other cases, there’s no clear cause.

Possible symptoms of prostatitis include discharge and:

  • pain
  • foul-smelling urine
  • blood in the urine
  • difficulty urinating
  • a weak or interrupted urine stream
  • pain when ejaculating
  • difficulty ejaculating

In some cases, prostatitis resolves on its own or with treatment within a few days or weeks. This type of prostatitis is known as acute prostatitis. But chronic prostatitis sticks around for at least three months and often doesn’t go away with treatment. Treatment may help relieve symptoms, though.

Smegma is a buildup of a thick, white substance under the foreskin of an uncircumcised penis. It’s made up of skin cells, oils, and fluids. Smegma isn’t actually discharge, but it looks very similar.

All of the fluids and components of smegma naturally occur on your body. They help keep the area hydrated and lubricated. But if you don’t regularly wash your genital region, it can start to build up and cause discomfort. Learn how to properly remove smegma.

Smegma also helps create a moist, warm environment. This can increase your risk for a fungal or bacterial infection.

Balanitis is inflammation of the foreskin. It tends to happen in people with uncircumcised penises. While it can be quite painful, it’s usually not serious.

In addition to discharge, balanitis can also cause:

  • redness around the glans and under the foreskin
  • tightening of foreskin
  • odor
  • discomfort or itchiness
  • pain in the genital area

Several things can cause balanitis, including:

  • skin conditions, such as eczema
  • fungal infections
  • bacterial infections
  • irritation from soaps and other products

If you’ve ever had any type of sexual contact, it’s important to rule out an STD as a potential cause of your discharge. This can be done with simple urine and blood tests.

Gonorrhea and chlamydia are two of the most common causes of penile discharge. They require treatment with prescription antibiotics.

Keep in mind that STDs don’t just result from penetrative intercourse. You can contract an STD by receiving oral sex and engaging in nonintercourse activities.

And some STDs don’t cause symptoms immediately. This means you could still have an STD, even if you haven’t had any sexual contact in months.

Left untreated, STDs can cause long-term complications, so it’s important to treat them. This also reduces your risk for transmitting an infection to others.

While penile discharge is often a symptom of an STD, other things can cause it, too. Regardless of the cause, it’s best to follow up with a doctor to diagnose and treat any underlying conditions, especially bacterial infections.

While you’re figuring out what’s causing your discharge, it’s best to avoid any sexual activity with others to avoid transmitting any potential infections to them.