It's normal and healthy to produce a clear or white discharge from your vagina.

This mucus is produced naturally from the neck of the womb, known as the cervix.

The amount of vaginal discharge varies throughout your menstrual cycle (brown discharge is usually the end of your period) and most pregnant women will get a "pregnancy discharge".

Healthy discharge doesn't have a strong smell or colour. You may feel an uncomfortable wetness, but you shouldn't have any itching or soreness around your vagina.

How do I know if my discharge is unhealthy?

Any sudden change to your discharge may indicate a vaginal infection. You should be aware of how your discharge naturally varies throughout your cycle and what isn't normal, but obvious warning signs of infection are:

• a change in colour or consistency
• a sudden bad smell
• an unusually large amount of discharge
• another symptom alongside the discharge, such as itching outside your vagina or pain in your pelvis or tummy
• unexpected bleeding from the vagina

If you're not sure whether your discharge is normal and are worried about it, see your GP or nurse. Read about sexual health for general information and advice.

Common causes of abnormal discharge

There are many possible causes of abnormal vaginal discharge, but it's usually a sign of infection. The infection is often caused by something that upsets the natural balance of bacteria or yeast in your vagina, such as washing inside the vagina, or it may be sexually transmitted.

The most common causes are:

• thrush – a fungal infection that commonly affects the vagina
• bacterial vaginosis – a bacterial infection of the vagina
• trichomoniasis – a sexually transmitted infection (STI) caused by a tiny parasite
• gonorrhoea or chlamydia – STIs caused by bacteria
• genital herpes – an STI caused by the herpes simplex virus

The guide below may help you identify the cause of your discharge. However, it's important to see your GP for a proper diagnosis and advice on how to treat the infection.

Watery or white vaginal discharge with intense itchiness

If your discharge is thin and watery, or thick and white (like cottage cheese), you may have thrush. This common fungal infection causes intense itchiness and soreness around your vagina. The discharge may smell slightly yeasty, but doesn't have a strong smell.

Almost all women get thrush from time to time and it's not sexually transmitted. It's easily treated with antifungal medicine, which can be bought over the counter from your pharmacist.

White or grey fishy-smelling discharge

If your vaginal discharge is grey or develops a strong fishy smell, particularly after sexual intercourse, you could have bacterial vaginosis (BV). BV is an imbalance in the normal bacteria found in your vagina. It doesn't usually cause itching or irritation.

Like thrush, BV is very common and isn't sexually transmitted. It's easily treated with antibiotics. See your GP for a prescription.

Green, yellow or frothy discharge

Trichomoniasis is a common STI caused by a tiny parasite. It can make your vaginal discharge frothy, yellow or green. You may have a lot of discharge, which may also have an unpleasant fishy smell. Other possible symptoms are soreness, swelling and itching around the vagina, and pain when passing urine.

Trichomoniasis is easily treated with an antibiotic called metronidazole, which your GP will prescribe. If you have trichomoniasis, visit a local GUM or sexual health clinic as it can exist alongside other STIs.

Abnormal discharge with pain or bleeding

See your GP or go to a genitourinary medicine (GUM) clinic as soon as possible if your vaginal discharge is abnormal and you have:

• pain in your pelvis
• pain when you urinate
• bleeding between periods or after sex

You may have chlamydia or gonorrhoea (both STIs). Gonorrhoea can make your discharge turn green, although often the pain or bleeding are more noticeable. Both conditions are treated with antibiotics.

Untreated gonorrhoea or chlamydia may spread upwards and lead to pelvic inflammatory disease, a serious infection of the womb, fallopian tubes or ovaries.

Abnormal discharge with blisters around the genitals

Genital herpes can cause painful, red blisters or sores to appear around your genitals, as well as an abnormal vaginal discharge. See your GP or go to a genitourinary medicine (GUM) clinic as soon as possible. You may be offered a course of antiviral tablets, which stop the herpes virus multiplying, but the symptoms may have a tendency to return.

Young girls and post-menopausal women

It's unusual for young girls to have abnormal vaginal discharge before they've gone through puberty. If this happens, they should see a GP. A common cause is a type of vulvitis (inflammation of the vulval area), caused by a streptococcal infection.

Abnormal discharge is also unusual in older women. If you've gone through the menopause and suddenly notice an abnormal vaginal discharge, see your doctor as soon as possible. Possible causes include:

• a sexually transmitted infection (STI)
• cervical polyps – non-cancerous growths in the womb or lining of the cervix (neck of the womb)
• an intrauterine device (IUD)

It's also important to rule out cervical cancer or endometrial cancer.

Cleaning your vagina

The vagina is self-cleansing, so there is no need to wash inside it (called douching). Douching can upset the natural balance of bacteria and fungi in your vagina and lead to thrush or bacterial vaginosis.

Vaginal soreness and abnormal vaginal discharge can also be caused by overusing perfumed soaps, bubble baths and shower gels. Never clean your vagina with anything strongly perfumed. Use a mild soap and warm water to gently wash around your genitals.