Using lactulose for vulvovaginal dysbiosis/infections

Lactulose is a form of sugar used medically in the digestive tract as a treatment for constipation (a laxative). Lactulose selectively feeds certain bacteria and is considered a prebiotic.

Lactulose is not absorbed in the intestine like other forms of sugar, meaning it can travel through the digestive tract to the large intestine. When lactulose gets to the large bowel, it provides a food source for bacteria there, but also draws water to the intestine and stimulates the bowels as a laxative. Lactulose is an artificial FODMAP.

The full treatment instructions for using lactulose effectively are in the ultimate guide to treating bacterial vaginosis, Killing BV.

Using lactulose in the vagina

Lactulose can be used in the vagina to selectively feed lactobacilli while actively starving bacterial vaginosis-related pathogens. However, lactulose can feed some pathogens – check which bugs love lactulose.

Research has demonstrated that lactulose does not feed yeasts or bacterial vaginosis, making it an effective way to increase vaginal lactobacilli counts.

Lactulose actively limits the growth of Candida albicans and Atopobium vaginae and does not affect (as in, does not limit or promote) the growth of Gardnerella vaginalis, Prevotella bivia, or Mobiluncus curtisii.

Top vaginal warriors, Lactobacillus crispatus, L. gasseri and L. jensenii, had growth broadly and easily stimulated by lactulose. Lactulose was preferred over other sugars as a food source.

Lactulose can also lower vaginal pH, getting the vagina back to a healthy pH of between 3.5 and 4.5. This acidity change is likely due to the extra activity of lactic-acid-producing bacteria, lactobacilli.

What is lactulose?

Lactulose is made from milk sugar, lactose. Raw milk does not contain lactulose but is created in milk during the heating process (pasteurisation).

The higher the heat, the more lactulose is produced. Lactulose is an isomer of lactose, created by one molecule each of fructose and galactose. Lactulose is a disaccharide, with di meaning two, and saccharide meaning sugar. Disaccharide means two sugars together.

Where to buy lactulose

Order lactulose here.

How to use lactulose vaginally

We like to put the lactulose into vegetable capsules, which come with the My Vagina Lactulose Kit.

Lactulose safety

Lactulose may require medical advice in some countries when used orally for treating diarrhoea. Lactulose may contribute to health problems if it is used too much or used incorrectly.

When used vaginally these cautions do not apply since the liquid is not entering the digestive tract and is not absorbed into the bloodstream.

Do not continually use lactulose outside of treatments, as it may result in lactobacillus overgrowth, which can produce some uncomfortable symptoms.

How does lactulose work?

Lactulose is not broken down by enzymes in the human digestive system or vagina and therefore remains as a source of food for bacteria and microbes that can use it. Lactobacilli, the protective vaginal bacteria that you want to keep around, can utilise lactulose.

Lactulose safety and effectiveness (pregnancy, breastfeeding)

Lactulose has been used medically since the 1950s and is considered by the World Health Organisation as an essential medicine.

There have been no reports of harm from using during pregnancy and is considered safe to use during breastfeeding.


  1. 1.
    Collins SL, McMillan A, Seney S, et al. Promising Prebiotic Candidate Established by Evaluation of Lactitol, Lactulose, Raffinose, and Oligofructose for Maintenance of a Lactobacillus-Dominated Vaginal Microbiota. Elkins CA, ed. Appl Environ Microbiol. Published online March 2018. doi:10.1128/aem.02200-17

Original price was: USD $9.95.Current price is: USD $0.00. ex GST/VAT/TAX
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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)