Is blood in urine a symptom of an STI?

Blood in your urine is not a usual symptom of an STI. The NHS and UK sexual health guidelines don’t list it as a symptom of Chlamydia, Gonorrhoea, Trichomonas, Mycoplasma genitalium or genital Herpes.

These infections are more likely to cause pain when you pee, unusual discharge, or bleeding after sex or between periods, which can sometimes be mistaken for blood in your pee. Gonorrhoea can occasionally spread to the prostate and cause prostatitis, which can lead to blood in your urine.

Because blood in your pee has many possible causes, including cancer, get it checked by a doctor as soon as you can, even if you think an STI is to blame.

Blood in your pee may make it look bright pink, red or dark brown. This is sometimes called visible blood. Sometimes the amount of blood is too small to see, and it only shows up when your urine is tested. The blood may not be there all the time, and it can come and go.

It may not be blood in your pee if:

• you’ve recently eaten beetroot, which can turn your pee pink
• you’re taking a new medicine, as some medicines can turn pee red or brown
• you’re on your period
• you’re bleeding from your vagina between periods, or from your bottom

If you’re not sure, see a doctor, who can test a urine sample.

Urinary tract infections

A urinary tract infection (UTI) can cause blood in your pee, as well as burning pain when peeing, needing to pee more often, and cloudy or smelly pee. UTIs aren’t STIs, but sex can make them more likely, and some STIs cause very similar symptoms. Read more in “Is a UTI an STI?”

Kidney infections

A kidney infection is a type of UTI that has spread to the kidneys. As well as blood in your pee, it can cause a high temperature, pain in your side or lower back, and feeling sick. A kidney infection can be serious if it isn’t treated, as it can cause sepsis. Get urgent medical care if you feel confused or drowsy, or find it hard to speak.

Kidney stones

Kidney stones can cause bad pain in your side, lower back or groin that comes and goes, and blood in your pee.

An enlarged prostate

An enlarged prostate is common in men over 50. It can make it hard to pee, and cause a sudden need to pee and waking up at night to pee. It can sometimes cause blood in your pee.

Prostatitis

Prostatitis is an inflamed prostate gland. It is usually caused by an infection, such as a UTI. Gonorrhoea can sometimes spread from the urethra and cause it, and Trichomonas rarely does.

Cancer

Blood in your pee is the main symptom of bladder cancer. It can also be a sign of kidney or prostate cancer. This is why it’s important to see a doctor, even if the blood goes away.

Other causes

Other causes include medicines that thin the blood, very hard exercise such as long-distance running, and bilharzia, an infection caught from fresh water like rivers and lakes in some countries abroad. If you take a blood thinner and see blood in your pee, get medical help straight away, and don’t assume the medicine is the only cause.

Some STIs cause symptoms that can be confused with blood in your urine.

Chlamydia

Chlamydia usually causes no symptoms. When it does, it can cause a burning feeling when you pee, unusual discharge from the vagina or penis, bleeding after sex or between periods, and pain, bleeding or discharge from your bottom.

Gonorrhoea

Gonorrhoea doesn’t always cause symptoms. It can cause burning pain when you pee and unusual discharge. It rarely causes bleeding between periods. In men, it can sometimes spread to the prostate or testicles.

Trichomonas

Trichomonas can cause pain when peeing, needing to pee more often, and unusual discharge. Many people have no symptoms.

Mycoplasma genitalium

Mycoplasma genitalium often causes no symptoms. In men, the most common symptoms are discharge and irritation in the tube you pee through (the urethra). In women, it has been linked to bleeding after sex.

Genital Herpes

Herpes can cause painful sores or blisters and pain when you pee. In a first outbreak, it can sometimes stop you being able to pee. If you can’t pee at all, get urgent medical care. Read more in “Is it Herpes or a UTI?”

Urethritis

Inflammation of the urethra, the tube you pee through, is called urethritis. It is usually caused by an STI and can cause discharge and pain when peeing. Read more in “What is non-specific urethritis (NSU)?”

See a doctor as soon as you can if you have, or think you have, blood in your pee. Do this even if:

• you have no pain
• it only happened once
• you think it’s caused by an STI

A doctor may ask about your symptoms, test a sample of your urine, arrange a blood test, or refer you to a specialist for more tests. If you can’t pee at all, get urgent medical care.

If you also have symptoms of an STI, such as unusual discharge, pain when peeing, or sores, or you have had sex without a condom with a new partner, get tested for STIs too. A negative STI test doesn’t rule out other causes of blood in your pee, so still see a doctor.

If you have symptoms that could be caused by an STI, the right test depends on your symptoms and the kind of sex you have had:

• Comfort Screen: a urine test for 8 infections that can cause genital symptoms: Chlamydia, Gardnerella, Gonorrhoea, Herpes 1, Herpes 2, Mycoplasma, Trichomonas and Ureaplasma. You can test from 14 days, with results in 2 days at one of our clinics. It is also available as a home test kit.
• Blemish Screen: if you have a sore, blister or lump on or around your genitals, it tests a swab for Herpes 1, Herpes 2, HPV and Syphilis.
• Platinum Screen: our most comprehensive STI screen, which tests for 12 infections, from 28 days.

Not sure which test you need? Our Patient Care Team is available 24/7 on 020 7099 0955.

Chlamydia, Gonorrhoea and Trichomonas can usually be cured with antibiotics:

• Chlamydia is usually treated with doxycycline tablets, taken twice a day for 7 days.
• Gonorrhoea is usually treated with a single injection of an antibiotic called ceftriaxone.
• Trichomonas is usually treated with metronidazole tablets, most often twice a day for 7 days.

To lower your risk of STIs, use condoms every time you have sex, and test regularly if you have new or casual partners. Vaccines can protect against HPV and Hepatitis B, and since August 2025, the NHS in England has offered a vaccine that gives some protection against Gonorrhoea to people at higher risk, mainly gay, bisexual and other men who have sex with men.

Can Chlamydia cause blood in your urine?

It isn’t a usual symptom. Chlamydia is more likely to cause a burning feeling when you pee, or bleeding after sex or between periods, which can be mistaken for blood in your pee.

Can a UTI be caused by sex?

UTIs aren’t STIs and can’t be passed to a partner, but sex can move bacteria towards the urethra and make a UTI more likely. Peeing soon after sex may help. Read more in “Can men get UTIs?”

Is blood in your urine serious?

It usually isn’t caused by anything serious, but it always needs checking because it can be a sign of cancer. See a doctor as soon as you can, even if it only happened once.

Blood in your pee is rarely caused by an STI. It is more often caused by a urine infection, kidney stones or an enlarged prostate, and it can sometimes be a sign of cancer, so always see a doctor as soon as you can.

If you also have symptoms of an STI, get tested. Book a Comfort Screen at a clinic near you or order a home test kit. Our Patient Care Team is available 24/7 on 020 7099 0955.

Not in the UK? Choose your country from the selector at the top of the page for local tests and prices.

This article originally appeared on 12 July 2024 and was last updated on 30 September 2026.

Medical review. This article was medically reviewed by Dr Steve Chapman, Doctor with a wealth of clinical experience in the field of STIs, on 30 October 2024. It is general information and not a substitute for personal medical advice.

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