How to Avoid Ear Infections After Freediving: What the Evidence Says About Vinegar, Alcohol, and Olive Oil

If you spend a lot of time in the water — freediving, surfing, pool training — you have probably had an outer ear infection. The dull ache, the itch, and the "no diving for a week" verdict. I used to get them every other month until we started rinsing our ears after sessions.

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.

I also have some corrections to make. The earlier version of this article told you to avoid alcohol-based drops. That contradicts what Divers Alert Network actually recommends, and I got it wrong.

Correction: DAN recommends vinegar together with alcohol

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 — divers who skipped that part saw their infections return.

So my original "don't use alcohol" line is withdrawn.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 — but as a preventive drying agent in a healthy ear, it is part of the standard recommendation, not the enemy.

Olive oil I will stand behind: it 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.

Correction: how strong, and how long

I previously suggested using neat 5% white vinegar for 20–30 seconds. Two problems.

The published trials all used diluted acetic acid — 1% or 2%, meaning roughly a 1:2 to 1:5 dilution of household vinegar. And the protocol that made the difference for Navy divers required five minutes of contact time, not thirty seconds. If you are going to do this, follow the DAN 50/50 vinegar-and-alcohol mix and give it time to work.

The honest state of the evidence

Here is the part nobody says out loud: there are no trials demonstrating that prophylactic acetic acid drops prevent otitis externa in divers. The American Academy of Family Physicians' 2023 evidence review on acute otitis externa notes that some clinicians recommend 2% acetic acid solutions preventively, but that no trials have demonstrated the effectiveness of any of these preventive measures.

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 (2011–2013) 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 — but the difference was not statistically significant (p = 0.156), and 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.

Why it plausibly works

Your ear canal is normally slightly acidic, and cerumen helps maintain 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. Aggressive cleaning with cotton swabs makes it worse by removing wax and creating micro-abrasions.

Acetic acid restores the acidic environment. That is the mechanism, and it is sound. Sound mechanism plus no preventive trials is exactly the situation you should describe honestly rather than overclaim.

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.

My routine

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

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

When to stop and 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.

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.

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

Sources

• Swimmer's Ear, Divers Alert Network
• Swimmer's Ear (Otitis Externa), Divers Alert Network
• Ears and Diving, Chapter 4: Hygiene, Divers Alert Network
• Otitis Externa: Can You Prevent It?, Alert Diver Europe
• Acute Otitis Externa: Rapid Evidence Review, American Family Physician (2023) — notes no trials demonstrate preventive efficacy
• Role of Acetic Acid Irrigation in Medical Management of Chronic Suppurative Otitis Media: A Comparative Study (Gupta, Agrawal & Gargav), Indian J Otolaryngol Head Neck Surg
• Efficacy of diluted vinegar in treating granular myringitis: a randomised controlled trial (Prakairungthong et al., 2021), J Laryngol Otol
• Effectiveness of 1 and 2 per cent acetic acid solutions in the 2-week treatment of granular myringitis, J Laryngol Otol
• Efficacy of acetic acid versus ciprofloxacin ear drops in achieving dry ears in chronic suppurative otitis media, Gomal Journal of Medical Sciences — summarises the conflicting trials
• A SNP in the ABCC11 gene is the determinant of human earwax type (Yoshiura et al., 2006), Nature Genetics