References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
Different STIs cause different types of vaginal discharge — colour, consistency, smell and amount all vary. Not all discharge changes are STIs (BV and thrush are also common), but recognising patterns helps decide when to test. Here’s a practical comparison.
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Discharge by Cause
| Cause | Discharge Type |
|---|---|
| Chlamydia | Often none; thin, watery if present |
| Gonorrhoea | Yellow-green, thicker |
| Trichomoniasis | Frothy, yellow-green, foul-smelling |
| BV | Thin, grey, fishy odour |
| Thrush | Thick, white, clumpy |
| Normal | Clear or milky, mild odour |
When to Test
- Change from your usual pattern
- Unusual colour, smell or amount
- Discharge with itching, pain or bleeding
- Recent new partner
Read more: STI discharge guide | Discharge colours | Vaginal infections
Frequently Asked Questions
Can I tell which STI I have from discharge?
Not reliably — testing gives proper diagnosis.
Is all discharge abnormal?
No — normal discharge varies with your cycle.
Should I test if discharge is my only symptom?
Yes, especially with a new partner.
Related reading
- Can You Test for STIs While on Your Period?
- Cold Sores vs Syphilis Sores: How to Tell the Difference
- Common STI Symptoms in Women
- Do STIs Always Have Symptoms?
- Does a Vaginal Yeast Infection Smell?
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
