An infection in the vagina is usually caused by a bacterial imbalance. The vagina contains many types of bacteria. Some help it to stay clean and free from infections, whereas others can cause infections and other problems. Your vagina should contain enough of the ‘good’ bacteria to fight off the ‘bad’ bacteria, but sometimes the balance becomes uneven. 

Too much bad bacteria can lead to an infection, and the type of bacteria determines what infection you have. 

We’ve outlined the most common types of vaginal infections below, what causes them, some of the symptoms and how to treat them. 

What are the types of vaginal infections?


Chlamydia is one of the most common sexually transmitted infections (STIs) in the UK. It’s caused by a type of bacteria called Chlamydia Trachomatis. According to health specialists Bupa, 7 out of 10 women don’t experience any symptoms of Chlamydia. This means that regular STI checks are very important, particularly as Chlamydia can cause infertility and pregnancy complications if left untreated. 

If you have Chlamydia, you may notice pain when you have sex or when you go for a wee and your discharge could be cloudy and yellow. You may also experience bleeding between periods, abnormal discharge that has an odour and itching or burning around the vaginal area.

Even if you don’t have any symptoms, Chlamydia can still be passed on to other people, so it’s best not to take this risk and make sure you’re checked over regularly by a doctor. 

It’s likely that your doctor will ask for a urine sample or swab sample from inside the vagina. If the test comes back positive, Chlamydia may be treated with a course of antibiotics prescribed by your doctor. The antibiotics will help to kill the bacteria in your vagina, therefore getting rid of the infection. You should avoid having sex until you’ve finished your course of treatment.


Gonorrhoea, like Chlamydia, may not show any symptoms. It is caused by a type of bacteria known as Neisseria Gonorrhoeae and can be contracted via sexual contact with another infected person. 

You may begin to experience signs of Gonorrhoea around ten days after you’ve had unprotected sex. These symptoms may include vaginal discharge that’s thin and a green/yellow colour, pain or burning when weeing and pain in the lower abdomen. You should consult your doctor immediately who will advise a suitable course of treatment. In women, Gonorrhoea can spread to the womb, uterus, fallopian tubes and the ovaries. If this happens, you’re at risk of pelvic inflammatory disease which can lead to infertility and ectopic pregnancy. 

Bacterial Vaginosis (BV)

Bacterial Vaginosis is a type of infection that’s caused by a natural imbalance in the vagina. The infection is a result of the ‘bad’ bacteria outweighing the ‘good’ bacteria. BV isn’t considered a sexually transmitted infection; however, it can be passed from one female to another during sex. It cannot be passed onto, or contracted from, men. It isn’t just contracted during sex but can come about from the use of overly scented products, such as tampons, toilet roll, sanitary pads, body wash and bubble bath.

You may have BV if you notice discharge that smells fishy and has a thin and watery consistency. It may also be an off-white or grey colour. These are the main symptoms of BV, however some women don’t experience any symptoms at all. 

BV can usually be treated with antibiotic tablets or creams and gels. If you are concerned about BV you should seek advice from your doctor to know more about your options.


Thrush isn’t a bacterial infection, like the ones we’ve mentioned above. Instead, it is a yeast infection that is caused by fungus that exists naturally in the body. Around half of women have yeast growing in their vagina, but it’s mostly harmless. However, there may be certain triggers that can cause the yeast to grow too much, which leads to Thrush. 

The thrush symptoms for men and women are very different. Women may experience white vaginal discharge that has a very thick consistency. You may also notice itching and irritation in the vaginal area as well as burning during sex or when you wee.

Some common conditions or products that can cause Thrush include antibiotics, pregnancy and diabetes. Some women have to be careful about the soaps they use, while tight-fitting clothing may also be a contributory factor. 

Genital Herpes

Genital Herpes is another example of an STI that isn’t caused by bacteria. Herpes is a virus and there isn’t currently a cure for it. The most common symptom is sores around the vaginal area. It’s likely that your symptoms will come and go - they may remain dormant for some time, and then flare up. These flare ups usually occur when you drink lots of alcohol, smoke or are stressed. You may be able to prevent your symptoms from worsening by trying to avoid alcohol and cigarettes completely. 

If your symptoms worsen, you can speak to your doctor about options that may reduce your symptoms. 


Trichomoniasis is another STI, but this type is caused by a parasite called Trichomonas vaginalis. As with all STIs, it’s passed from person to person via unprotected sex. According to the NHS up to half of people don’t experience any symptoms, but you can still pass the infection onto other people.

The symptoms of Trichomoniasis are not dissimilar to those of Chlamydia, but you may also experience less frequent but heavier periods and discharge that is a yellow-green colour. Trichomoniasis can be treated with a course of antibiotics. 

What causes a bacterial vaginal infection?

Most of the infections we’ve mentioned above are STIs, which means they can only be passed during sexual contact. With others, such as BV and Thrush, it can be difficult to tell how the infection started. You could make some small lifestyle changes, such as avoiding overly scented washing powder, soaps or sanitary products or tight-fitting clothes or underwear. Consult your doctor for advice if you are unsure.

Your intimate area is sensitive so you need to treat the skin gently. Avoid soaps and body washes that contain colourants or strong fragrances.

Vaginal infection symptoms

Each infection comes with its own symptoms, but we’ve included some of the most notable vaginal infection symptoms below: 

  • Pain when you have sex
  • Pain when you wee
  • Unusual discharge (thin, watery, off-white, green, yellow, or foul-smelling)
  • Itchiness in or around the vagina
  • Pain in your lower tummy
  • Bleeding between your periods or after you have sex
  • Warts or ulcers around the vulva
  • Vaginal itching or soreness
  • Consult your doctor for advice on the best treatment for you.