How Do Different STDs Affect Your Vaginal Discharge?

You have noticed something different. The colour, the consistency, the smell. And now you are trying to match what you see against what you have read online, hoping to figure out whether this is normal variation or something that needs a test.

This guide covers how different STIs affect discharge in women and men, what the changes typically look like, and when to get tested. A comparison table is included for quick reference.

One important caveat before you read on: discharge alone cannot diagnose an STI. Infections overlap in their symptoms, and several STIs cause no discharge changes at all. Testing is the only way to confirm or rule out an infection.

"Discharge changes are your body communicating that something may have shifted. Rather than guessing, a simple swab or urine test can identify the cause and guide treatment."

Dr Hikmat Naoum, Consultant Gynaecologist, GMC 3047637

What does normal discharge look like?

Normal vaginal discharge is clear to white, has a mild or no odour, and changes in consistency throughout the menstrual cycle. Around ovulation, discharge becomes clearer and more slippery (similar to egg white). After ovulation and before menstruation, it tends to become thicker and whiter. These changes are driven by oestrogen and progesterone and are completely normal.

The volume of discharge also varies between women. Some women produce very little; others notice it daily on their underwear. Both are within the normal range provided the discharge is not accompanied by itching, burning, strong odour, or an unusual colour.

In men, small amounts of clear pre-ejaculate or slight moisture at the urethral opening are normal. Any visible discharge from the penis outside of arousal or urination warrants clinical assessment.

STD discharge in women: what to look for

Chlamydia

Chlamydia is frequently asymptomatic in women; roughly 70% have no noticeable symptoms. When it does affect discharge, the change is often subtle: slightly increased volume, a mild yellowish tint, or a mildly unpleasant odour. The discharge is usually not dramatically different from normal, which is why many women dismiss it.

Other possible symptoms include pain during urination, bleeding between periods, and lower abdominal discomfort. But for the majority, the first sign of chlamydia is a positive test result, not a visible symptom.

Gonorrhoea

Gonorrhoea can cause a thicker, more noticeable discharge than chlamydia. The colour is typically yellow or green, and the volume may be increased. Some women also experience bleeding between periods and pain during urination.

However, up to half of women with gonorrhoea have no symptoms at all. The discharge, when present, can be confused with other vaginal infections, making testing the only reliable way to distinguish gonorrhoea from other causes.

Trichomoniasis

Trichomoniasis produces one of the more distinctive discharge patterns. The discharge is typically yellow-green, frothy, and accompanied by a strong, unpleasant odour. Many women also experience vulval itching, soreness, and discomfort during sex.

The frothy quality is a useful distinguishing feature, though it is not present in every case. Around 50% of women with trichomoniasis are asymptomatic (BASHH, 2024).

Herpes

Herpes does not typically change vaginal discharge in a characteristic way. During an active outbreak, increased watery discharge may occur alongside blisters or ulcers on the genitals. The primary concern with herpes is the visible sores rather than discharge.

Bacterial vaginosis (not an STI)

BV is the most common cause of abnormal vaginal discharge (NICE CKS, 2024) in women of reproductive age. The discharge is thin, greyish-white, and has a characteristic fishy smell that often worsens after sex. BV is not classified as an STI but is more common in sexually active women and is frequently tested for alongside STIs.

Thrush (not an STI)

Vaginal candidiasis (thrush) produces thick, white, cottage-cheese-like discharge with a yeasty smell. It is accompanied by intense itching and vulval soreness. Thrush is caused by Candida fungus overgrowth and is not sexually transmitted.

Discharge comparison table

This table is a guide only. Colours and textures overlap between infections, and many STIs cause no discharge changes at all. Testing is the only reliable diagnostic method.

Yellow or green discharge

Yellow or green discharge can come from gonorrhoea, trichomoniasis, chlamydia or bacterial vaginosis, and the colour alone cannot tell them apart. Our guide to green or yellow discharge sets out each colour, its usual causes and which samples are needed. If you are not sure which test fits your symptoms, start with our unusual discharge testing page.

STD discharge in men

Men are more likely to notice discharge when it occurs, because any visible penile discharge outside of arousal is abnormal.

Chlamydia in men

Chlamydia causes discharge in approximately 50% of infected men. The discharge is typically clear or white, thin, and noticed first thing in the morning on underwear. It is often described as a "watery drip" rather than thick or coloured discharge. Other symptoms in men can include pain during urination and testicular discomfort.

Gonorrhoea in men

Gonorrhoea in men is more likely to be symptomatic than in women. The classic presentation is a thick, yellow-green or white discharge from the penis, often described as "dripping." It typically appears within 2-5 days of exposure and is accompanied by burning during urination.

This is one of the more recognisable STI presentations, but even gonorrhoea can be mild or absent in some men, particularly in rectal and pharyngeal infections.

Non-gonococcal urethritis (NGU)

NGU causes a clear or white discharge from the penis with discomfort during urination. It is caused by organisms other than gonorrhoea, most commonly chlamydia, mycoplasma genitalium, or ureaplasma. The discharge is typically less profuse than gonorrhoea.

If you have noticed any penile discharge, testing is straightforward. A chlamydia and gonorrhoea urine PCR is £104, with results within 3 working days. Walk in seven days a week. If you need everything back faster, the FAST Screen returns all results in 6 hours: FAST Screen Simple (£350) covers HIV, syphilis, chlamydia and gonorrhoea, and FAST Screen Complex (£450) adds hepatitis B and C.

When to get tested

Any new or changed discharge warrants testing if it has lasted more than a few days, is accompanied by other symptoms (pain, itching, odour, bleeding), has appeared after sexual contact with a new partner, or is different from your normal baseline.

Even if your discharge looks like thrush or BV based on the table above, testing is worthwhile. Self-diagnosis is unreliable because infections overlap in presentation, and treating the wrong condition delays proper treatment.

Our Silver Screen (£325 men, £375 women) covers chlamydia, gonorrhoea, mycoplasma, trichomoniasis, ureaplasma, Gardnerella, herpes, syphilis, HIV, plus a bacterial swab for candida and BV in women.

Walk-in testing is available seven days a week. All samples processed by UKAS-accredited laboratories. You do not need to use your real name, and we accept cash payment.

If the discharge persists or your tests are negative

A negative STI result is useful: it rules out the infections you were tested for. If the discharge carries on, keeps coming back after treatment, or comes with pelvic pain or bleeding between periods, it may have a cause that is not an infection and needs a closer look.

For ongoing symptoms that need a gynaecological assessment, see a gynaecology consultation at Gynae Clinic.

Frequently asked questions

What does chlamydia discharge look like?

In women, chlamydia discharge is often slightly yellow with a mild increase in volume. In men, it is typically clear or white and thin. However, 70% of women and 50% of men with chlamydia have no discharge at all. A PCR test is more reliable than visual assessment.

Can you have an STD with normal discharge?

Yes. Most STIs, including chlamydia, gonorrhoea, HPV, and HIV, can be present with completely normal discharge. Asymptomatic infection is common.

Is green discharge always an STD?

Not necessarily. Green discharge can indicate gonorrhoea or trichomoniasis, but bacterial vaginosis and other non-sexually transmitted infections can also produce greenish discharge. Testing is needed.

How soon after sex does STD discharge appear?

It varies. Gonorrhoea discharge can appear within 2-5 days. Chlamydia typically takes 1-3 weeks. Trichomoniasis can take 5-28 days. Some infections produce no discharge at any stage.

References

• BASHH (2024). UK National Guidelines for the Management of Vulvovaginal Candidiasis.
• BASHH (2024). UK National Guideline for the Management of Bacterial Vaginosis.
• NICE CKS (2024). Vaginal discharge — Causes and assessment.
• UKHSA (2024). Sexually transmitted infections and screening in England.