All women have some discharge (fluid) from the vagina each day. It is usually clear or cloudy/white, but may be yellow when dried on clothing.

In mid-cycle, when you ovulate (one of your ovaries releases an egg) the discharge increases and becomes more clear and stringy. It also increases when you are pregnant, on the pill or sexually aroused.

Common vaginal infections

Many infections also cause a discharge. The commonest is a harmless yeast called thrush (candida albicans). It often produces a thick, white discharge, irritation or rash outside the vagina (the vulva), itching, pain with intercourse and burning with urination.

Antibiotics, pregnancy, diabetes and the pill often trigger thrush. It is rare in children and women after the menopause (unless on HRT). Thrush is usually treated with over-the-counter creams or tablets inserted into the vagina (not just applied to 'the outside'), and sometimes by oral (by mouth) tablets.

Bacterial vaginosis is also common and is usually harmless. It can cause a grey or white, frothy discharge with a fishy odour, often worse after sex. It does not usually produce itching or pain. This infection is treated with oral tablets but often relapses.

Trichomonas is a sexually transmitted infection. It causes a bubbly, yellow or green discharge, often in large amounts, also with a fishy smell. It may cause irritation of the vulva. Treatment is with oral tablets for the patient and her partner.

Gonorrhoea and chlamydia are also sexually transmitted and can cause a discharge. They are treated with antibiotics.

When to see the doctor

See your GP if you are concerned about your vaginal discharge or if you have:

• An increase in the amount of discharge or a change in the colour or smell.
• An irritation, itch, burning or rash.
• Painful intercourse, painful urination or pain in the pelvis.