Prevent Ear Infection While Diving: The 50/50 Vinegar Mix

Mix equal parts white vinegar and isopropyl alcohol, or vinegar, alcohol and distilled water. Fill each ear canal after every session and hold it there five minutes. Healthy ears only. That is DAN's preventive protocol, and no trial has ever shown it prevents an infection.

I am not a doctor and this is not medical advice. I am a Freediving Instructor Trainer and Functional Breathing Coach, sharing what worked for me and my students, and what I found when I went looking for the evidence behind it.

That last sentence of the recipe matters, so take it before the routine rather than after. The American Academy of Family Physicians' 2023 evidence review on acute otitis externa notes that some clinicians recommend 2% acetic acid solutions preventively, and that no trials have demonstrated the effectiveness of any preventive measure. Sound mechanism, no proof.

Preventing an ear infection while diving

The rinse, step by step

Nine years of this, and I still do it after every session:

Use a 50/50 mix of white vinegar and isopropyl alcohol, per DAN, or buy a commercial preventive drop.
After your dive or pool session, tilt your head and fill the ear canal.
Let it sit for five minutes, not thirty seconds.
Tilt the other way and let it drain.
Pat the outer ear dry with a clean towel. Never put a cotton swab in the canal.
Take rest days. Even with drops, ears need time away from moisture and pressure changes.

On a multi-day trip

This is where people get caught out. Four days of diving in Bali or Dahab is four days of a wet canal, and the infection usually surfaces on day three or four, not on day one. Rinse after every session, not just the last one of the day. Build a rest day into the week and treat it as part of the prevention rather than a day lost.

What does not work

Olive oil has no antimicrobial action, and it softens cerumen, which is the opposite of what you want when the problem is a canal that has lost its protective wax.

Neat 5% vinegar for thirty seconds does not match anything that has been studied. The published trials used diluted acetic acid, 1% or 2%, roughly a 1:2 to 1:5 dilution of household vinegar. And the US Navy saturation-diving protocol that made the difference required a full five minutes of contact: divers who cut it short saw their infections come back.

Cotton swabs make it worse. They strip wax and leave micro-abrasions in a canal that needs both intact.

Why it plausibly works

Your ear canal is normally slightly acidic, and cerumen maintains that. DAN's explanation is that prolonged moisture emulsifies the natural wax and shifts the canal towards alkaline, which lets opportunistic bacteria and fungi take hold. Acetic acid restores the acidic environment.

The mechanism is sound. Preventive trials do not exist. Describe it honestly rather than overclaiming it, which is what I should have done the first time I wrote this.

When not to use drops, and when to see a doctor

Do not use these drops if you have, or might have, a perforated eardrum, or ear tubes. This is the one that can cause real harm.
Do not start preventive drops once you already have symptoms. DAN is explicit about this: once it hurts, stop diving and get it looked at. Established otitis externa usually needs prescription drops.
Ear pain, discharge, hearing changes, or fever mean a doctor, not a home rinse.
Do not dive again until you are fully healed and cleared.

Can freediving damage your ears?

The sources on this page cover one thing: the outer canal, and the infections that start there. Prolonged water exposure, lost cerumen and an alkaline canal are what this rinse addresses, and repeated sessions without rest days make that worse.

They say nothing about the middle ear. Barotrauma, a burst eardrum and equalisation injury are a different mechanism with a different fix, and I am not going to improvise an answer about them here. If your ears hurt during a descent rather than after a session, that is an equalisation problem: take it to a certified instructor and to a doctor who dives.

Correction: DAN recommends vinegar together with alcohol

I have corrections to make, and they are the reason this article exists in the form it does. The earlier version told you to avoid alcohol-based drops. That contradicts what Divers Alert Network actually recommends, and I got it wrong.

DAN's guidance for repetitive multi-day diving is a mixture of equal parts white vinegar and rubbing (isopropyl) alcohol, or equal parts vinegar, alcohol, and distilled water. The two ingredients do different jobs: the acetic acid lowers pH to discourage bacterial growth, and the isopropyl alcohol dries the canal. Alert Diver's write-up of the US Navy saturation-diving protocol describes the same principle using Domeboro Otic (2% acetic acid with aluminium acetate, sodium acetate, and boric acid), with the note that the solution must sit in each canal for a full five minutes.

So my original "don't use alcohol" line is withdrawn. Alcohol can irritate an already-inflamed canal, which is a reasonable caution once you are symptomatic. As a preventive drying agent in a healthy ear, it is part of the standard recommendation.

The honest state of the evidence

The studies people cite, including the ones I cited, are about treating established ear disease, not preventing swimmer's ear in divers. They are worth knowing, but do not let anyone (me included) present them as proof.

Gupta et al.: chronic suppurative otitis media, not swimmer's ear

This prospective study of 100 patients in India (2011 to 2013) compared aural toilet plus 2% acetic acid irrigation against topical and systemic ciprofloxacin. Discharge resolved in 84% of the acetic acid group versus 58% of the antibiotic group, and perforations healed in 26% versus 14%.

Real result, published in a Springer journal. But note what it is: chronic middle ear disease with a perforated eardrum, treated in a clinic with suction and mopping. That is a different condition from the outer-canal infection divers get, and the patients were not randomised. Also note the direct implication for you: if your eardrum is perforated, do not put anything in your ear without a doctor.

Other trials of the same comparison have gone the other way. A review of this literature summarises a randomised trial in which ciprofloxacin drops achieved dry ears in 73% of cases against 24% for 1% acetic acid, and a Kenyan trial where ciprofloxacin beat antiseptic drops. The literature is genuinely mixed.

Prakairungthong et al.: a proper RCT, with a null result

This one I reported incorrectly before. I wrote that vinegar produced results "faster" than antibiotic drops. It did not.

The randomised controlled trial (Siriraj Hospital, Bangkok, published in the Journal of Laryngology & Otology in 2021) enrolled 24 patients with granular myringitis and compared 1% diluted vinegar against 1% chloramphenicol drops. Eleven of 12 recovered on vinegar versus 8 of 12 on chloramphenicol, and the difference was not statistically significant (p = 0.156). With 12 people per arm this study could not have detected much. The authors' conclusion was that diluted vinegar is "an interesting option", noting its low cost and that it does not drive antimicrobial resistance. They also reported side effects: dizziness and mild ear canal irritation.

A follow-up double-blind RCT by the same group found no difference between 1% and 2% acetic acid over two weeks, with a 10% recurrence rate afterwards.

So the honest summary: diluted acetic acid is cheap, plausible, roughly comparable to topical antibiotics for some ear conditions in small trials, and unproven as a preventive for divers.

The earwax question

There are two cerumen types, wet (sticky, honey-coloured) and dry (flaky, grey), and this genuinely is genetic. A single nucleotide polymorphism in the ABCC11 gene, rs17822931, determines it: the AA genotype gives dry earwax, GA and GG give wet. Frequency of the dry-type allele is highest in East Asian populations, essentially 100% of the Han Chinese and Korean samples in the original study, and lowest in African and European populations.

That part is solid. What I claimed next was not. I wrote that dry earwax means you can dive for weeks without worrying while wet-earwax divers get infections after a few days. I could not find any study linking cerumen type to otitis externa risk in divers. I inferred it from the lipid composition and from watching who in my classes got infections. That is an interesting hypothesis and I am leaving it in as exactly that, not as a fact, and not as a reason to relax your ear care if you happen to have dry wax.

Bottom line

A vinegar-and-alcohol rinse is cheap, has a plausible mechanism, is the standard recommendation from DAN and the US Navy, and has never been proven in a preventive trial. It stopped my infections and my instructors' infections. That is real-world experience, not evidence, and you deserve to know the difference.

Before the next in-water session, the two pages worth reading are the breath-hold safety guide and the freediving schools map if you want an instructor watching your ears and everything else.

Author MJ Kühn Freediving Instructor Trainer & Functional Breath Coach Co-Founder of breathhold.co