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Non-gonococcal urethritis (NGU) can have a number of possible causes, such as an infection, irritation or damage to the urethra.

There are also many cases where no cause is found – this is sometimes known as non-specific urethritis (NSU).

Sexually transmitted infections (STIs)

If urethritis is caused by gonorrhoea, it is known as gonococcal urethritis.

NGU can also be caused by other sexually transmitted infections (STIs), such as chlamydia. Chlamydia is spread during unprotected sex (sex without a condom), including anal and oral sex.

Urethritis is more common among people who are at risk of STIs. This includes people who:

Other infections

A number of other infections can cause NGU. These are caused by other bacteria that usually live harmlessly in the throat, mouth or rectum.

These bacteria can cause NGU if they get into the urethra, which is the tube that carries urine from the bladder to the outside of the body. This can occur during oral or anal sex.

Infections that can cause NGU include:

Non-infectious causes

It's possible for NGU to have a non-infectious cause. This is when something else leads to the urethra becoming inflamed. 

Non-infectious causes of NGU include: