Course length, effectiveness, side effects and the practical factors that decide which one suits you.
Part of the Bacterial Vaginosis condition guide.
Get medical help first. Contact NHS 111 (NHS 24 on 111 in Scotland) or your GP the same day if you have pain in your lower tummy or pelvis, a high temperature or you feel unwell. If you’re pregnant, speak to your midwife about any change in discharge. Visit a sexual health clinic if you have bleeding between periods or after sex, sores or blisters, or a partner who has been diagnosed with an STI. Online treatment is not suitable in these situations. If your symptoms started after sex with a new partner, we can still treat BV, but please also get a free STI test.
Key fact: All three first-line BV treatments have broadly similar cure rates. The decision is almost always about alcohol, condoms, tolerability and course length — not about one being stronger than the others.
Get BV Treatment Online
Access Doctor’s GPhC-registered pharmacist independent prescribers assess BV symptoms online and, where treatment is suitable, supply it from our UK pharmacy. Approved before 3pm, Monday to Friday? Dispatched the same day in plain packaging, by Royal Mail Tracked 48, Tracked 24 or Special Delivery guaranteed by 1pm next working day: you choose.
Start a BV consultation →Adults only online, and not in pregnancy or breastfeeding. Access Doctor’s online BV service is for adults aged 18 and over who aren’t pregnant or breastfeeding. If that isn’t you, your GP, midwife or a local sexual health clinic can assess and treat BV free of charge. Under 18? NHS sexual health clinics see young people confidentially.
The three options side by side
Three treatments are used first line for bacterial vaginosis in the UK. All are prescription-only. Two are metronidazole in different forms, and one is a different antibiotic entirely.
| Metronidazole tablets | Zidoval gel | Dalacin 2% cream | |
|---|---|---|---|
| Active ingredient | Metronidazole 400mg | Metronidazole 0.75% | Clindamycin 2% |
| Route | Oral tablet | Vaginal gel | Vaginal cream |
| Course | Twice daily, 7 days | One applicator nightly, 5 nights | One applicator nightly, 7 nights |
| Alcohol | None during the course and for 48h after | Reaction unlikely, but avoid for 48h after to be safe | No restriction |
| Affects latex condoms | No | Not listed in its leaflet | Yes — during treatment and for 72 hours after |
| Typical side effects | Nausea, metallic taste, appetite loss | Local irritation, discharge, some thrush | Local irritation, thrush |
| Systemic absorption | Most of the dose | Minimal | Minimal |
| Use in pregnancy | Under clinical supervision | Under clinical supervision | Under clinical supervision |
Which one suits your situation
People often ask us which one is “best”. Honestly, it depends on you, so it’s more useful to start from your own circumstances. This table maps the most common deciding factors onto the option that usually fits.
| If this applies to you… | Usually the better fit | Why |
|---|---|---|
| You do not want to avoid alcohol | Dalacin 2% cream | Clindamycin has no alcohol interaction; metronidazole tablets do, and caution is advised with the gel |
| You rely on latex condoms or a diaphragm | Metronidazole tablets or Zidoval gel | Dalacin can weaken latex during treatment and for 72 hours after the last dose |
| Oral antibiotics make you nauseated | Zidoval gel or Dalacin cream | Minimal systemic absorption means far less nausea and metallic taste |
| You want the shortest course | Zidoval gel | Five nights, versus seven for Dalacin and 7 days for tablets |
| You would rather not use an applicator | Metronidazole tablets | Oral dosing avoids vaginal administration entirely |
| You are taking warfarin or lithium | Dalacin, or tablets with monitoring | Oral metronidazole interacts with both; discuss with your prescriber |
| You have had several oral courses already | Zidoval gel | Also the preparation used twice weekly for suppression in recurrent BV |
Diagnosis first. This comparison assumes BV has been confirmed or is clinically likely. If you are not sure whether your symptoms are BV or thrush, start with BV vs thrush — none of the treatments below will help if the problem is a yeast overgrowth.
Metronidazole tablets
Oral metronidazole 400mg twice a day for 7 days (14 tablets) is the NICE CKS first-line option, the treatment most women are given, and the course Access Doctor supplies. It is well established, inexpensive and does not require vaginal administration.
- Taken with or after food, which reduces nausea considerably.
- No alcohol during the course or for 48 hours after the last dose.
- Nausea, a persistent metallic taste and reduced appetite are the usual complaints.
- Interacts with warfarin and lithium — declare all your medicines at consultation.
- The main practical drawback is the alcohol restriction over a full week.
Full detail on dosing, timing and missed doses is in how to take metronidazole, and the complete side effect picture is in metronidazole side effects and warnings. If you want background on the antibiotic itself, see what metronidazole is and what it treats.
Zidoval vaginal gel
Zidoval delivers the same antibiotic directly to the site of the problem. One applicator is inserted at night for five consecutive nights — the shortest standard course of the three.
Because very little metronidazole is absorbed into the bloodstream, the systemic side effects that make the tablets unpopular are largely avoided. Its leaflet says a reaction with alcohol is unlikely but can’t be ruled out, so it’s sensible to avoid alcohol during the course and for 48 hours after. The leaflet also advises against using it during your period or having sex during treatment. It’s currently out of stock with us, but your GP or a sexual health clinic can prescribe it.
Five nights only
The shortest first-line course, which some women find easier to complete than a seven-day oral regimen.
Minimal systemic effects
Much less nausea and metallic taste than tablets, because little of the drug reaches the bloodstream.
Also used for suppression
Twice weekly for around 16 weeks is a recognised specialist approach for genuinely recurrent BV.
Go easy on alcohol
A reaction is unlikely with the gel, but to be safe avoid alcohol during the course and for 48 hours after.
Application technique and the full cautions are covered in Zidoval vaginal gel for BV: how to use it.
Dalacin 2% cream
Dalacin is clindamycin rather than metronidazole, which makes it the option of choice when metronidazole is unsuitable — whether because of intolerance, an interaction, or simply because avoiding alcohol for a week is impractical. One applicator is inserted at night for seven consecutive nights. It’s currently out of stock with us, but your GP or a sexual health clinic can prescribe it.
Latex warning. Dalacin cream weakens latex condoms and diaphragms. Do not rely on them for contraception or protection against sexually transmitted infections during the course or for 72 hours after the last application. Use an alternative method for that period.
Clindamycin can also cause diarrhoea, and persistent or severe diarrhoea during or after a course should be reported rather than treated at home. It isn’t suitable if you have inflammatory bowel disease or have had colitis with an antibiotic before. Detailed guidance is in Dalacin 2% cream for BV: how it works and how to use it.
How effectiveness actually compares
The honest answer is that the differences are small. UK guidance treats all three as first-line options, and head-to-head trials have not established a decisive winner. What differs meaningfully is tolerability and convenience — which is why the decision table above is more useful than a ranking.
3
First-line options in UK guidance, with similar results
2–3 days
Before most women notice clear improvement
Up to 30%
Come back within 3 months, whichever is used
That last figure is the one that matters most and is least often mentioned. Recurrence is common with every option, which is why the choice of first-line treatment is much less important than what happens if episodes keep returning. See recurrent BV for how repeat episodes are managed, and how long BV takes to clear up for what to expect during the course itself.
On pharmacy alternatives. Lactic acid gels such as CanesBalance are sold over the counter and can help with symptoms, but the UK VITA trial found them less effective than metronidazole for clearing an active episode. Our guide to BV gels compared looks at these options in full.
Pregnancy, breastfeeding and recurrence
Three situations change the picture and need a clinician who can see you, rather than an online consultation.
1
Pregnancy
Symptomatic BV in pregnancy is generally treated, usually with oral metronidazole, but always under the care of a clinician who knows you are pregnant. Our online service doesn’t treat BV in pregnancy, so speak to your midwife, GP or a sexual health clinic.
2
Breastfeeding
Metronidazole passes into breast milk and can affect its taste. Our online service doesn’t treat BV while you’re breastfeeding, so speak to your GP or a sexual health clinic, who can advise on the safest option for you and your baby.
3
Repeated episodes
If this is your third episode of BV in 12 months, see your GP or a sexual health clinic: recurrent BV is managed differently — extended courses, suppressive twice-weekly gel and systematic trigger management, rather than repeating a standard course each time.
Get BV Treatment Online
Complete a short online consultation and our GPhC-registered pharmacist independent prescribers will check whether treatment is right for you. Approved before 3pm, Monday to Friday? Dispatched the same day in plain packaging, by Royal Mail Tracked 48, Tracked 24 or Special Delivery guaranteed by 1pm next working day: you choose.
Start a BV consultation →UK safety and getting treatment
Every antibiotic treatment for BV in the UK, whether tablets, gel or cream, is a prescription-only medicine. Before anything is prescribed, a GPhC-registered pharmacist independent prescriber reviews your consultation, including your allergies and the other medicines you take. Always read the patient information leaflet in the pack. Never share antibiotics with anyone else, and don’t keep leftover tablets for next time: return unused medicine to a pharmacy.
If you think you’ve had a side effect from a medicine, tell your pharmacist or doctor. You can also report it to the MHRA through the Yellow Card scheme, which helps keep medicines safe for everyone.
You can get BV treatment free from your GP or a sexual health clinic, and many clinics offer walk-in appointments and STI testing at the same visit. Our private online service is an alternative for adults aged 18 and over who aren’t pregnant or breastfeeding. You can see all our BV treatment online options on one page.
Frequently Asked Questions
Which BV treatment is most effective?
Oral metronidazole, Zidoval vaginal gel and Dalacin 2% cream all work about as well as each other for a first episode, and UK guidance lists all three as first-line options. The choice is usually driven by tolerability, alcohol, contraception and personal preference rather than by a meaningful difference in effectiveness.
Which BV treatment can I use if I do not want to avoid alcohol?
Dalacin 2% cream contains clindamycin and carries no alcohol restriction. With metronidazole tablets, avoid alcohol during the course and for 48 hours afterwards. With Zidoval gel a reaction is unlikely, but the same caution is sensible.
Which BV treatment is safe with latex condoms?
Metronidazole tablets do not affect latex, and the Zidoval leaflet does not list a latex warning. Dalacin 2% cream can weaken latex condoms and diaphragms, so don’t rely on them for contraception or protection during the course and for 72 hours after the last application.
What is the shortest course of BV treatment?
Zidoval vaginal gel is the shortest standard course at five nights. Oral metronidazole is 7 days and Dalacin 2% cream is seven nights. A single 2g dose of metronidazole exists, but BV comes back sooner after it, so it isn’t routinely recommended and Access Doctor doesn’t supply it.
What if I cannot tolerate oral antibiotics?
The vaginal preparations are the appropriate alternative. Because far less drug reaches the bloodstream, Zidoval gel and Dalacin cream cause much less nausea and metallic taste than oral metronidazole while achieving similar cure rates.
Which BV treatment is used in pregnancy?
Symptomatic BV in pregnancy is usually treated with oral metronidazole, but this must be managed by a clinician who knows you are pregnant. Our online service doesn’t treat BV in pregnancy, so speak to your midwife, GP or a sexual health clinic.
Can I switch treatment if the first one does not work?
Yes, and switching between drug classes is a recognised approach. If a full metronidazole course has not resolved symptoms, a prescriber may move you to clindamycin, or reconsider whether the diagnosis is correct. Do not repeat the same course without advice.
Can I buy BV treatment over the counter in the UK?
Not the antibiotics. Metronidazole tablets, Zidoval gel and Dalacin cream are all prescription-only, so you need a GP, a sexual health clinic or a regulated online prescriber. Lactic acid gels are sold in pharmacies and can ease symptoms, but they are less effective than metronidazole at clearing an episode.
Completing the treatment
Access Doctor currently supplies metronidazole tablets, after an online consultation with a pharmacist independent prescriber. Zidoval gel and Dalacin cream are out of stock with us, so if one of those suits you better, your GP or a sexual health clinic can prescribe it. Tell us about alcohol plans, contraception and any previous courses in the consultation.
Bacterial vaginosis · Rx
Metronidazole 400mg Tablets
The usual first-choice BV treatment: one tablet twice a day for 7 days, after an online consultation.
View →Bacterial vaginosis
BV Treatment Online
All our BV options in one place, including when to see your GP or a sexual health clinic instead.
View →References
- National Institute for Health and Care Excellence. Clinical Knowledge Summaries: Bacterial vaginosis. 2025. cks.nice.org.uk
- Electronic Medicines Compendium. Zidoval 7.5mg/g Vaginal Gel — Summary of Product Characteristics. medicines.org.uk
- Electronic Medicines Compendium. Dalacin 2% Cream — Summary of Product Characteristics. medicines.org.uk
- Armstrong-Buisseret L, Brittain C, Hepburn T, et al. Lactic acid gel versus metronidazole for recurrent bacterial vaginosis: the VITA RCT. NIHR Health Technology Assessment, 2022. ncbi.nlm.nih.gov
- British Association for Sexual Health and HIV. National guideline for the management of vaginal discharge. bashh.org
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.