Lactobacillus overgrowth syndrome (cytolytic vaginosis)

While lactobacilli is one of the most helpful microorganisms in the human vaginal tract, it isn’t always good news if this generally-friendly bacteria get out of control and one species dominates.

Typically lactobacillus overgrowth syndrome, also known as cytolytic vaginosis (CV), has a high lactobacillus crispatus count, typically 98 per cent and above. We don’t know why this occurs. CV often appears to switch with aerobic vaginitis (AV), so treatment can be tricky unless you have an experienced practitioner.

Overuse of probiotics or lactulose can result in a temporary overgrowth of lactobacilli, but unless you have underlying causes (excess oestrogen, diabetes), this won’t turn into CV. CV is when the single lactobacillus species has completely dominated the microbiome and won’t give an inch.




When lactobacilli overgrow, it can look and feel like a yeast infection, but this condition won’t respond to antifungals. Cytolytic vaginosis can go on for a long time undiagnosed because all the classic markers of a problem are not apparent – it seems like a healthy vaginal microbiome.

How do I know if I have cytolytic vaginosis?

The best way to determine if you have CV is to get a comprehensive microbiome test, and talk to an experienced practitioner about your results. Your symptoms and test results will help determine if you have CV, but importantly, your practitioner can help work out why.

CV does not occur in healthy vaginas.

When a suspected (untested) yeast infection doesn’t respond to antifungals, over and over, and when probiotic use makes the problem worse. Cytolytic vaginosis tends to be cyclic, as the food supply relies heavily on oestrogen to stimulate glycogen. This means symptoms will get worse at certain times of your menstrual cycle when oestrogen is high.

Higher oestrogen times are during the middle of your cycle, around ovulation, with another smaller spike between ovulation and your period. If you are on hormonal contraceptives, oestrogen levels tend to stay stable, so you may experience symptoms less cyclically, but they will drop off during your period.

If your microbiome has being thoroughly tested, and seems to switch from CV to AV, look into histamine intolerance and examine contributing factors i.e. oestrogen.

How cytolytic vaginosis works

Cytolytic vaginosis is also called lactobacillus overgrowth syndrome or Doderlein’s cytolysis, and is characterised by an overgrowth of lactobacilli species. This overgrowth actually damages the vaginal cells and results in the cell wall rupturing and the cell dying.

cyto means cell
lytic means death

cytolytic vaginosis is therefore a condition involving the disintegration of the vaginal cell wall

Normal functioning of lactobacilli in the vagina

A healthy vagina has an abundance of lactobacilli species that work to ward off invaders like E. coli, Candida albicans and glabrata, and various other species like Gardnerella vaginalis. Lactobacilli produce hydrogen peroxide and lactic acid, among other bacteriocins, in their normal daily war against all things not vagina, including HIV.

Lactobacilli do a great job, using glucose as a food source, taken from the vaginal wall and provided by the action of oestrogen.

In a normal vagina, the presence of low numbers of lactobacilli has been shown to have a protective effect against yeast infections by blocking the adhesion of the yeasts to the vaginal walls as they compete for nutrients.

Some women in their fertile years, however, may develop an overgrowth of lactobacilli, which alone (or sometimes with other bacteria) can cause damage to the vaginal walls that results in the cells dying. This causes vaginal discharge.

This discharge is then misdiagnosed as a yeast infection and antifungals are prescribed. Women with diabetes (any kind) may have an overabundance of glycogen (vaginal glucose) due to blood sugar dysregulation, which feeds the lactobacilli and allows their overgrowth.

Symptoms may also increase during the luteal phase (the part of the cycle post-ovulation until the first day of the period), which is where oestrogen rises, possibly causing more glycogen to be excreted and feeding the lactobacilli.

Symptoms of cytolytic vaginosis

  • The signs and symptoms are much like a yeast infection
  • Itching
  • Painful sex or penetration attempts (dyspareunia)
  • Discharge (usually thick and white, may be clumpy)
  • Burning
  • Irritation
  • Soreness
  • Cyclical increase in symptoms (in the luteal phase after ovulation)

How often is cytolytic vaginosis diagnosed?

While it isn’t usually the primary focus of a doctor’s visit, there are some stats available. In one study (Cerikeioglu et al 2004​1​), 210 women with vaginal discharge and other symptoms that looked like a yeast infection were examined, and 15 of them were found to have cytolytic vaginosis.

Another study (Wathne et al 1994​2​) found around five in 101 women had cytolytic vaginosis.

It is estimated that while yeast infections comprise up to 30 per cent of all gynaecological complaints associated with discharge, cytolytic vaginosis makes up between five and seven per cent of those in the same patient population. It is considered a significant clinical condition. 

Diagnosis of cytolytic vaginosis

A yeast infection and BV must be excluded by further investigations. This is done by testing the following:

  • Normal pH is found in cytolytic vaginosis (3.5-4.5)
  • Leukocytes (white blood cells involved in immune responses) are not observed in cytolytic vaginosis, whereas they are in yeast infections
  • Typical yeast cells are not found
  • Bacterial vaginosis is excluded by pH tests and the whiff test (BV presents with an alkaline vagina, more than 4.5)
  • Negative culture results in sabouraud dextrose agar (SDA) (for testing for certain fungi)

To diagnose cytolytic vaginosis, the following must be true:

  • Increased lactobacilli numbers
  • No TrichomonasGardnerella or Candida on a wet mount
  • Few white blood cells
  • High suspicion
  • Discharge
  • pH between 3.5 and 4.5

Treating cytolytic vaginosis

Reducing lactobacilli numbers can be done by elevating the vaginal pH using a sodium bicarbonate douching solution or suppository. This should help to restore the natural balance after three weeks, however if symptoms worsen, stay the same or become different, cease treatment and seek re-evaluation.

Cytolytic vaginosis douche bicarb treatment mixture

  • 1-2 tablespoons of baking soda (sodium bicarbonate)
  • 4 cups of warm water

Douche twice-weekly for one week on, one week off, for three weeks.

Cytolytic vaginosis suppository bicarb treatment mixture

  • Empty vegetable capsules (not gelatin), size 0 or 1 is fine
  • Fill with baking soda

Insert one capsule deep into the vagina twice a week for one week on, one week off, for three weeks.

When should I see results from the bicarb treatment?

Each of you will be a bit different, but the treatment period is over several weeks and therefore the results will also be over several weeks – but, you should feel some relief immediately.

Don’t overdo this treatment, as you don’t want to go in the other pH direction too far and leave your vagina open to other pathogens. Avoid probiotics and milk kefir (anything containing lactobacilli) for your treatment time, and make sure you evaluate why this has been allowed to occur.

If you are not sure, seek the help of a qualified, experienced healthcare provider who is knowledgeable about bacteria and women’s health. Your naturopath may be a good place to start, as you get way more time with your practitioner than your regular GP.

What do I do if I don’t respond to the bicarb?

Testing and treatments is haphazard at best, with this condition not even necessarily an official condition. Researchers are still learning about it, and therefore many doctors are unaware of how to test for or treat lactobacillus overgrowth. We spend so much time trying to get these good bacteria to proliferate and make themselves at home, it is somewhat counterintuitive to now see them as the enemy.

We suggest you see a practitioner who either knows about cytolytic vaginosis or is willing to learn, who wants to help you. This is easier said than done, but there are many types of practitioner out there. It doesn’t have to be a doctor.

A naturopath, herbalist, acupuncturist, or nutritionist may be able to shed some light on what they think is going on, and help restore balance.


  1. 1.
    Cerikcioglu N, Beksac MS. Cytolytic Vaginosis: Misdiagnosed as Candidal Vaginitis. Infectious Diseases in Obstetrics and Gynecology. Published online 2004:13-16. doi:10.1080/10647440410001672139
  2. 2.
    Wathne B, Holst E, Hovelius B, Mårdh P-A. Vaginal discharge – comparison of clinical, laboratory and microbiological findings. Acta Obstet Gynecol Scand. Published online January 1994:802-808. doi:10.3109/00016349409072509

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Jessica Lloyd - Vulvovaginal Specialist Naturopathic Practitioner, BHSc(N)

Jessica is a degree-qualified naturopath (BHSc) specialising in vulvovaginal health and disease, based in Melbourne, Australia.

Jessica is the owner and lead naturopath of My Vagina, and is a member of the:

  • International Society for the Study of Vulvovaginal Disease (ISSVD)
  • International Society for the Study of Women's Sexual Health (ISSWSH)
  • National Vulvodynia Association (NVA) Australia
  • New Zealand Vulvovaginal Society (ANZVS)
  • Australian Traditional Medicine Society (ATMS)