Thrush is inflammation of the vagina caused by a yeast infection. It is not sexually transmitted as the yeasts that cause thrush are very common - they occur in the bowel, on the skin and in the environment.
It mainly causes itching in the genital area but can also cause soreness, redness, swelling and a white, lumpy discharge.
Thrush is really common - 75% of women will have one episode in their lifetime and 45% will have two or more episodes.
The natural hormone oestrogen seems to play an important role in problems from thrush so it is more common at times when oestrogen levels are higher - e.g. during your reproductive years and during pregnancy. It is also more common among people with diabetes, those who have taken a recent course of antibiotics and those who are immuno-suppressed.
No-one knows why some women suffer more with thrush than others.
The aim of treatment is to get rid of the symptoms - not necessarily to get rid of the infection.
To do this you can use anti-fungal creams (usually clotrimazole) in the vagina or anti-fungal tablets (usually fluconazole) - you can get both these medications from the chemist without a prescription.
The important thing is to check that your symptoms really are thrush - these are symptoms of irritation - redness, itchiness, swelling, pain - usually on the skin of the genitals. And if it is thrush then these symptoms should get better with treatment. If they do not then it is worth a visit to your GP or sexual health clinic to make sure that the problem that you are treating really is thrush.