What's normal
It's normal to have some vaginal discharge, as the vagina stays moist as part of its self-cleansing mechanism. The normal moist discharge clears dead cells and bacteria from the vagina. It comes mainly from glands in the cervix (the neck of the womb), and is slightly acidic, which helps to keep infections at bay. The acidity results from lactic acid, formed by 'friendly' bacteria as they break down sugars.

The amount of normal discharge varies from woman to woman, and with the menstrual cycle. Many women notice that during the week after a period there is hardly any discharge, and what there is has a thick consistency. Towards the middle of the cycle (about 2 weeks after the start of a period) the amount increases and it becomes thin, slippery and clear, like uncooked egg white. When this discharge is exposed to the air it becomes brownish-yellow, so it is normal to find a yellowish stain on your undies at the middle of the monthly cycle. There may also be a feeling of moistness and stickiness.

Discharge also increases during pregnancy. And during sexual excitement, vaginal discharge becomes very profuse because two glands near the vaginal opening (the Bartholin's glands) secrete additional slippery mucus, which acts as a lubricant for intercourse.

Abnormal discharge
Normal discharge doesn't smell, and does not cause any irritation or itching. A discharge is likely to be abnormal if:

• it smells fishy
• it's thick and white, like cottage cheese
• it's greenish and smells foul
• there's blood in it (except when you have a period)
• it's itchy
• you have any genital sores or ulcers
• you have abdominal pain or pain on intercourse
• it started soon after you had unprotected sex with someone you suspect could have a sexually transmitted disease.

Possible causes

• bacterial vaginosis
• thrush
• forgotten tampons
• gonorrhoea
• trichomoniasis

• what is thrush?
• True or false? (myths about thrush)
• Dr Margaret's advice

• during pregnancy
• when you take antibiotics (because these get rid of the friendly bacteria)
• if you have diabetes, especially if your blood sugar levels are consistently too high
• if you wear tight, non-porous underwear, such as nylon knickers and tights (because Candida thrives in warm, moist conditions)
• if the vulva or vagina is sore for any other reason, particularly if you scratch (because damaged tissue is more susceptible to Candida)
• if you are ill for any reason
• if you are taking any drugs, such as steroids, which lower the body's resistance to infection

True or false? (Myths about thrush)

The contraceptive pill causes thrush
Probably false. Doctors are still arguing about this, but there is very little evidence for it.

Thrush is always sexually transmitted
False. Women who are not sexually active can suffer from thrush. The Candida yeasts are already in the vagina, and they cause thrush when the body's natural balance that keeps it under control is upset.

Thrush always causes a discharge
False. Itching is the usual symptom of thrush - there is often no discharge at all, or just a slight discharge.

Thrush is very smelly
False. If there is an odour, it is minimal and not unpleasant.

Thrush can be prevented by douching the vagina
Very definitely false. Douching is squirting a soapy or antiseptic solution into the vagina to 'cleanse' it. There is no need to do this, because the vagina cleans itself very efficiently. In fact, douching has the opposite effect; it destroys the 'friendly' bacteria, gets rid of the healthy acidity and damages the lining, allowing thrush and other infections to take hold easily.

Treating thrush

Forgotten tampons
'Lost' tampons are quite a common cause of discharge. It is easy to forget to remove the last tampon at the end of a period. After a week or two, the tampon begins to fester, and there will be a foul-smelling discharge.

If you have an old tampon in place, remove it as soon as possible. If your discharge continues for more than a couple of days, see your doctor or visit a genito-urinary medicine clinic.

Gonorrhoea
Gonorrhoea is one of the most infectious sexually transmitted diseases. If a woman has unprotected sex with a man who has it, she has a 60-90% chance of catching it. It's a serious infection caused by the Gonococcus bacterium. It's serious because if it isn't treated, it can spread upwards to the Fallopian tubes, and cause infertility. About one-fifth of women with gonorrhoea have a foul-smelling, greenish-yellow discharge. About one-fifth have vague symptoms, such as a slight increase in discharge, pain on intercourse or lower abdominal discomfort. About one-fifth have no symptoms at all. (Most men with gonorrhoea notice an obvious discharge.)

Trichomoniasis
This is caused by a tiny amoeba-like (protozoan) organism called Trichomonas vaginalis. It used to be common, but for mysterious reasons is becoming less so; over the last 10 years the number of cases in England and Wales has fallen from 17 000/year to 5000/year. It causes a discharge that is often frothy and yellowish-greenish, but it may be thin and scanty. The discharge is smelly, and the vulva is often sore. It may also be painful to pass urine. It is caught from a man who has it, but he may be unaware of his condition as most men with trichomoniasis don't have any symptoms. It's not dangerous, though some doctors think it could possibly spread to the Fallopian tubes.

Treatment

• general advice
• if you think you have thrush
• other conditions

General advice
For any vaginal problem, you must take care to avoid substances that may cause more irritation. These are the same as those that can cause vulval irritation, so look at the common-sense steps listed in that section. During a period, change tampons or sanitary pads frequently (at least two or three times a day), and don't use tampons when it isn't your period. Ask your partner to go to a clinic for a check-up if your doctor advises he does so, or if he has any discharge from the urethra (the opening at the end of the penis) or any soreness or irritation of the penis.Don't have sex until the problem has been sorted out.

If you think you have thrush
If your discharge is thick and white and itchy it may be thrush, so you could try an anti-thrush cream or tablet from a pharmacist. If your discharge has a different colour and/or is foul-smelling, you should go to a genito-urinary medicine clinic for a check-up. These clinics can do on-the-spot tests for most of the causes of vaginal discharge, and you can attend without a referral from your GP.Even if you are fairly sure it is thrush, don't persist with an anti-thrush cream from the pharmacist if it doesn't resolve the problem in a day or two, or if the discharge returns. See your doctor or go to a clinic to get a proper diagnosis.

Other conditions
Each cause of vaginal discharge has its own proper treatment, which could be a cream or tablet, and it's important to follow the treatment instructions from your doctor or the clinic very carefully. If you're asked to return for another check-up, it's important that you do so, even if the discharge has gone. The clinic may be checking for gonorrhoea, which can damage your Fallopian tubes and infect a future sexual partner without you having any further symptoms.

Tests that may be needed
A doctor will look at the vulva for any signs of thrush, and will then insert a metal device called a speculum into the vagina, in order to look at your vagina. Samples of the discharge can be taken by wiping with cotton-wool swabs. A family physician will usually have to send the swabs to a laboratory, so it may be some days before the result is available. A genito-urinary medicine clinic can look at the samples under the microscope straight away, and can usually tell you the diagnosis within half an hour, though they are also sent to the main laboratory for confirmation. Don't be surprised if you see the doctor or nurse testing the acidity of the discharge with litmus paper, or mixing some of it with a liquid (potassium hydroxide) on a glass slide and then sniffing it; these are standard tests for bacterial vaginosis.

• Vaginal and vulval problems main page
• Painful vulva
• Vulval itching
• Fishy smell
• Vaginal discharge
• Change in colour
• Dry vagina
• Genital lumps (female)
• Vaginal lips
• Genital infections
• Common sense dos and don’ts
• Useful contacts