What causes penile discharge, and when to get tested

You noticed a mark in your underwear, or a drop at the tip when you woke up. Maybe it stings a little when you pee. Now you're searching late at night, and every page seems to say something different.

Here's the plain answer. Men do get discharge, and it nearly always means the urethra is inflamed. An STI is the most common cause, with chlamydia and gonorrhoea at the top of the list, but a urine infection, prostatitis or an infection under the foreskin can do it too. An examination and a urine test usually tell which within a day or two.

If you'd rather skip the reading, our doctors see men with discharge seven days a week at our Harley Street clinic, walk-in or booked. You'll find what's included and the prices on our penile discharge page.

Is some discharge from the penis normal?

A few fluids are a normal part of having a penis. Pre-ejaculate is a small amount of clear, slippery fluid that appears when you're aroused. Semen comes with ejaculation. Smegma is a white, cheesy build-up of skin cells and natural oils under the foreskin, and it washes away with warm water.

Anything else that comes out of the opening at the tip, that isn't urine or semen, counts as penile discharge. That's worth getting checked, even when it's small and painless.

What causes penile discharge?

Doctors call inflammation of the urethra urethritis. When gonorrhoea is the cause, it's gonococcal urethritis. Everything else falls under non-gonococcal urethritis (NGU), sometimes called non-specific urethritis, which the NHS describes as the more common type. Chlamydia is the cause the NHS names first.

Common causes of penile discharge and how they tend to show up

Mycoplasma genitalium is worth a mention because it's easy to miss. It causes a share of NGU, it isn't picked up by a chlamydia or gonorrhoea test, and BASHH guidance recommends testing for it in men with urethritis. Trichomoniasis is less common than chlamydia or gonorrhoea, though it's often overlooked for the same reason.

The causes that aren't STIs matter too. Balanitis can follow thrush, washing too little or too harshly, or irritation from soap, shower gel or condoms, and the NHS notes that diabetes makes thrush more likely. Prostatitis can come on suddenly, often with a fever, or grumble on for months. If burning and needing to go often are your main symptoms, our guide to UTI or STI testing explains how the two differ.

What does the colour of the discharge mean?

Yellow or green discharge in men is the classic sign of gonorrhoea, and white, cloudy or watery discharge is more typical of chlamydia and NGU. That's why people search by colour. The trouble is that the overlap is large: chlamydia can look thick, gonorrhoea can look thin, and two infections can be present at once.

The one thing worth remembering is that where the discharge comes from tells a doctor more than its colour. Fluid from the opening at the tip comes from the urethra and points towards urethritis, which usually needs an STI test. A thick discharge collecting under the foreskin, with redness and soreness on the head of the penis, points towards balanitis, which is often thrush or a skin problem.

Either way, a test settles it. That's why BASHH guidance relies on laboratory testing rather than the look of the discharge.

When should you get tested?

If you have discharge now, come in now. The doctor can examine you, take samples, and where it's clinically appropriate start antibiotics the same day, before the results come back. BASHH guidance supports this kind of treatment for men with urethral discharge.

If you've had sex without a condom and have no symptoms yet, chlamydia and gonorrhoea tests become reliable around one to two weeks after the contact. Our guide to STI window periods sets out the timing for each infection, including HIV and syphilis.

If a partner has tested positive, get tested and treated even if you feel fine, because chlamydia in particular often causes no symptoms. And if you've already had a negative result but the discharge is still there, our article on STI symptoms with a negative test explains what a doctor checks next.

If discharge comes with a painful, swollen testicle or a fever, see a doctor the same day.

How is penile discharge tested?

The doctor asks about your symptoms and recent partners, examines you if appropriate, and collects a swab of the discharge and a urine sample. For men, a first-catch urine sample, the first part of the stream, is the standard sample for chlamydia and gonorrhoea testing, so it helps not to have peed for a while before you arrive.

The samples go to an accredited laboratory for NAAT testing, which looks for the organisms' genetic material. The combined chlamydia and gonorrhoea test costs £104 and returns results from 6 hours on the expedited service. STI screening packages return results in 24 to 72 hours.

Penile discharge prices at 117a Harley Street, October 2026

Most men with discharge choose the Bronze package, because it covers the examination, the main tests and the prescription in one visit. If your doctor thinks you need a wider screen, our sexual health clinic offers fuller packages and individual tests, and every extra test is priced and agreed with you first.

What happens after the results?

Your doctor contacts you with the results and confirms you're on the right treatment. If something needs a specialist, such as a urologist for prostatitis, we arrange the referral directly.

Results go to you only. We don't share anything with your NHS GP, employer or partner without your consent, and you can register under a different name if you prefer. If an STI is confirmed, the doctor will talk you through telling recent partners, so they can be tested and treated too.

Our sexual health service is led by Dr Mohammad Bakhtiar (GMC 4694470), who has seen patients at Medical Express Clinic for over 20 years.