Are Probiotics Good for Your Vagina? What the Trials Show

Live cultures can be good for the vagina in one well-measured way: taken after a course of antibiotics for bacterial vaginosis (BV), they were associated with BV recurrence of 14.8% against 25.5% across ten trials of 1,234 women. For thrush they add a short-term benefit to antifungal treatment and no lasting one (ten trials, 1,656 women, low to very low certainty), and for urinary infections six placebo-controlled Cochrane trials (352 people) found no significant effect (RR 0.82).^{1, 2, 3} Antibiotics and antifungals are the treatments; live cultures were studied around them, not in their place. This page is part of the Wellgard guide to what causes BV.

Sources checked on 29 October 2026.

Are probiotics good for your vagina?

Live cultures, usually sold as probiotics, are bacteria of the kinds that already dominate a healthy vagina, mostly lactobacilli, taken by mouth or as a pessary. Whether adding them changes anything you can measure depends on the outcome.

Can I get rid of BV by taking probiotics? takes the first row trial by trial.

Oral or vaginal: which route reaches the vagina?

Both routes have evidence, and they are not interchangeable. In the 2026 network meta-analysis, vaginal live cultures reduced recurrence after antibiotics with moderate certainty (RR 0.37) and oral with low (RR 0.45); a second 2026 meta-analysis of vaginal tablets alone found no effect (RR 0.86), so even the better-rated route is contested.^{4, 9} The best single vaginal trial is the 2020 NEJM study of a prescription-track L. crispatus product: 228 women, eleven weeks of use after metronidazole gel, recurrence 30% against 45%.¹⁰ For oral capsules the question is whether swallowed bacteria arrive, and the answer is strain by strain. One widely used lactobacillus colonised the gut in 79% of women and the vagina in 9.5%.¹¹ The two-strain capsule behind most oral BV trials raised vaginal lactobacilli from day 28 of a 60-day study.¹² Arriving is not the same as helping: across the ten trials, the route was unrelated to the size of the effect.¹ The label questions that matter follow from that.

Do probiotics cause more discharge, or throw off pH balance?

Neither has been shown. A healthy vagina is dominated by lactobacilli, which make lactic acid and hold the pH at around 3.5; "balance" is the wrong picture, because health is one group dominating, not good and bad bacteria in equal measure.¹³ Adding lactobacilli, where they take, pushes pH down towards that range. The condition where lactobacilli are too abundant, cytolytic vaginosis, produces itch, soreness and a thick white discharge that mimics thrush while swabs come back clear; a 2023 scoping review of 64 studies found no agreed diagnostic criteria and did not link it to supplements.¹⁴ If thrush treatment keeps failing, ask for a swab rather than guess. On discharge, no trial has reported live cultures increasing it, and the one trial that measured it reported less.⁸ A change in discharge during a course is more likely the condition than the capsule; the NHS lists a fishy smell, thick white discharge, green, yellow or frothy discharge, and discharge with pelvic pain or bleeding as reasons to get help.¹⁹

Do probiotics help with thrush?

As an add-on to antifungal treatment, a little and briefly. The Cochrane review of ten trials in 1,656 non-pregnant women found that live cultures taken alongside antifungals improved short-term clinical response (RR 1.14) and reduced relapse at one month (RR 0.34), with no long-term benefit and evidence rated low to very low.² A 2026 meta-analysis of 14 trials added the finding that matters most: used instead of antifungals, live cultures gave worse long-term mycological results (RR 0.52).⁵ Antifungals from a pharmacy or GP are the treatment, and the NHS says not to self-treat more than twice in six months without advice.¹⁶ Thrush after antibiotics is real: in one study, women given antibiotics were three times as likely to grow Candida afterwards, and six of 27 developed symptomatic thrush against none.¹⁷ Vaginal thrush: symptoms, causes, treatments and prevention covers recurrence, sugar and pregnancy.

Do probiotics make you taste better, or wetter?

No trial has measured either. What the trials did measure is smell: the three-month L. crispatus trial reported less odour alongside less discharge and itch.⁸ A fishy smell is the main symptom of BV and the thing to get swabbed; what probiotics make your vagina smell better? covers what live cultures can and cannot do about it.

What are the side effects, and who should take care?

Wind, bloating and a looser stool in the first days are the common ones and usually settle; what happens when you start taking women's probiotics? covers what to expect. The serious cases in the 2015 safety review were almost all in people with a weakened immune system, a central venous line, a serious illness or recent major surgery, where live bacteria occasionally reached the bloodstream; anyone in those groups, including anyone having chemotherapy or on immune-suppressing medicines, should review with a pharmacist or GP before starting.¹⁸ In pregnancy, the trials found no safety problems and no benefit, so speak to a GP or midwife.^{6, 7} The NHS says to see a GP or sexual health clinic if you think you have BV; for thrush, see a GP for a first episode, under 16 or over 60, more than four episodes in 12 months, failed treatment, pregnancy, breastfeeding or a weakened immune system; changed discharge, bleeding between periods or after sex, pain when peeing or pelvic pain are reasons to call NHS 111.^{15, 16, 19}

What we don't know

No trial has tested an oral live-culture capsule sold in the UK against placebo for BV recurrence in UK women; the ten pooled trials were run elsewhere, most oral ones with a single pair of strains.¹ The two 2026 reviews of the vaginal route disagree (RR 0.37 against 0.86), so whether a pessary beats a capsule is open.^{4, 9} For thrush no benefit has been shown beyond one month, and for urinary infections the Cochrane review could neither confirm nor rule out an effect.^{2, 3} No trial has measured taste, lubrication or libido, or followed women beyond a few months.

Frequently asked questions

Can probiotics throw off pH balance?

Not in the trials. Lactobacilli lower vaginal pH towards the healthy value of around 3.5, and the rare condition of too many lactobacilli, cytolytic vaginosis, has not been linked to supplements.^{13, 14}

Do probiotics make you taste better?

No trial has measured it. The outcomes measured are BV recurrence, Gram-stain scores and, in one trial, discharge, smell and itch.^{1, 8}

Can I use an oral capsule as a pessary?

No. The vaginal products in the trials were made for that route; an oral capsule is made to dissolve in the gut.⁴

Is it good for a woman to take probiotics every day?

In the ten pooled trials live cultures were used for 8 to 60 days; how do I take women's probiotics? covers timing, food and antibiotics.¹

Sources

1. Chieng WK, et al. Probiotics, a promising therapy to reduce the recurrence of bacterial vaginosis in women? A systematic review and meta-analysis of randomized controlled trials. Frontiers in Nutrition, 2022. Meta-analysis, 10 RCTs, 1,234 women. PubMed 36204368.
2. Xie HY, et al. Probiotics for vulvovaginal candidiasis in non-pregnant women. Cochrane Database of Systematic Reviews, 2017. Cochrane review, 10 RCTs, 1,656 women. PubMed 29168557.
3. Schwenger EM, Tejani AM, Loewen PS. Probiotics for the prevention of urinary tract infections in adults and children. Cochrane Database of Systematic Reviews, 2015. Cochrane review, 9 trials, 735 people. PubMed 26695595.
4. Gardella B, et al. Rethinking prevention of recurrent bacterial vaginosis: a comparative effectiveness network meta-analysis. Journal of Lower Genital Tract Disease, 2026. Network meta-analysis of RCTs. PubMed 42611724.
5. Chen R, et al. Probiotics for the treatment of vulvovaginal candidiasis in nonpregnant women: a systematic review and meta-analysis. American Journal of Obstetrics and Gynecology, 2026. Meta-analysis, 14 RCTs. PubMed 41547378.
6. Husain S, et al. Effects of oral probiotic supplements on vaginal microbiota during pregnancy: a randomised, double-blind, placebo-controlled trial with microbiome analysis. BJOG, 2020. RCT, 304 pregnant women. PubMed 30932317.
7. Yang S, et al. Effect of two oral lactobacillus strains on the vaginal microbiota, cytokines and chemokines in pregnant women. Nutrients, 2020. RCT, 86 pregnant women. PubMed 32019222.
8. Mändar R, et al. Impact of Lactobacillus crispatus-containing oral and vaginal probiotics on vaginal health: a randomised double-blind placebo controlled clinical trial. Beneficial Microbes, 2023. RCT, 182 women, three months. PubMed 36856121.
9. Awasthi Y, et al. Lactobacillus vaginal tablets and the prevention of recurrent bacterial vaginosis: a systematic review and meta-analysis. Probiotics and Antimicrobial Proteins, 2026. Meta-analysis, 8 RCTs, 562 women. PubMed 42234392.
10. Cohen CR, et al. Randomized trial of a vaginal Lactobacillus crispatus live biotherapeutic for recurrence of bacterial vaginosis. New England Journal of Medicine, 2020. Phase 2b RCT, 228 women. PubMed 32402161.
11. Colodner R, et al. Vaginal colonization by an orally administered lactobacillus strain. Israel Medical Association Journal, 2003. Open study, 42 postmenopausal women. PubMed 14650098.
12. Reid G, et al. Oral use of two lactobacillus strains significantly alters vaginal flora: randomized, placebo-controlled trial in 64 healthy women. FEMS Immunology and Medical Microbiology, 2003. RCT, 64 women. PubMed 12628548.
13. O'Hanlon DE, Moench TR, Cone RA. Vaginal pH and microbicidal lactic acid when lactobacilli dominate the microbiota. PLoS One, 2013. Observational study, 56 women. PubMed 24223212.
14. Kraut R, et al. Scoping review of cytolytic vaginosis literature. PLoS One, 2023. Scoping review, 64 studies. PubMed 36701339.
15. NHS. Bacterial vaginosis. Reviewed 19 June 2026. nhs.uk/conditions/bacterial-vaginosis.
16. NHS. Thrush in men and women. Reviewed 28 July 2023. nhs.uk/conditions/thrush-in-men-and-women.
17. Xu J, et al. Effect of antibiotics on vulvovaginal candidiasis: a MetroNet study. Journal of the American Board of Family Medicine, 2008. Pilot cohort, 80 women. PubMed 18612052.
18. Doron S, Snydman DR. Risk and safety of probiotics. Clinical Infectious Diseases, 2015. Narrative review. PubMed 25922398.
19. NHS. Vaginal discharge. Reviewed 15 February 2024. nhs.uk/conditions/vaginal-discharge.

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General information, not medical advice. Food supplements are not a substitute for a varied and balanced diet and a healthy lifestyle; do not exceed the recommended daily dose.