Is Hyperbaric Oxygen Therapy Safe? Risks, Side Effects, and Who Should Avoid It

For its established uses, delivered correctly and with proper screening, hyperbaric oxygen therapy is considered safe, and serious complications are uncommon. As Harvard Health notes, HBOT for FDA-approved conditions is regarded as safe, and complications are unusual though not impossible. That said, it is not entirely risk-free and it is not suitable for everyone. Understanding the side effects, the rare risks, and the situations where HBOT should be avoided is the responsible way to approach it.

The most common side effect: ear pressure

The most frequent issue people experience is pressure in the ears as the chamber pressurizes, the same sensation you feel on a plane. It happens because the pressure on either side of the eardrum needs to equalize. Swallowing, yawning, or gentle jaw movements usually resolve it.

According to clinical references on HBOT complications, the most common complication is barotrauma, meaning pressure-related injury to air-filled spaces, and the most common form of that is irritation or, rarely, rupture of the eardrum. This is exactly why a slow, controlled pressure change matters, and why you should signal to slow down if you cannot equalize comfortably. Sharp ear pain is a cue to pause, not to push through.

Other possible side effects

Less common effects associated with hyperbaric oxygen include temporary changes in vision that typically resolve after stopping a course of sessions, sinus discomfort, and tiredness after a session. Because oxygen at higher pressures can, in rare cases, affect the central nervous system, clinical references note that more serious hazards can include oxygen-related seizures, which is why high-pressure clinical protocols include safeguards. At the lower pressures used in mild HBOT, these higher-pressure risks are reduced, though sensible operation still matters.

Rare but serious risks

Serious complications are uncommon but worth naming honestly. The same clinical references list more serious injuries such as pneumothorax and damage to the ear canals, and note that the most catastrophic hazards are chamber fires and explosions. Because oxygen supports combustion, fire safety is a genuine consideration in any oxygen-rich environment. This is one of the strongest reasons that equipment quality, certified construction, and proper operating procedures are not optional extras but core to safe use.

Who should be cautious or avoid HBOT

HBOT is not appropriate for everyone. According to StatPearls clinical guidance, the only absolute contraindication is an untreated pneumothorax, meaning a collapsed lung, because altering the pressure can cause a life-threatening tension pneumothorax. Several other situations are relative contraindications that call for medical assessment first, including:

• Certain lung conditions such as COPD, where there is a risk of carbon dioxide retention
• Asthma and conditions that can trap air in the lungs
• People with specific implanted devices, which should be confirmed as pressure-compatible
• Those taking certain medications, including some chemotherapy drugs
• Recent ear or sinus surgery, or active ear or sinus infections
• Anyone unwell, congested, or with a fever on the day of a session
• Pregnant individuals, who should consult a clinician first

This is general information rather than a complete medical list, and a qualified clinician should assess individual suitability. A dedicated overview of who should not use a hyperbaric chamber goes into the contraindications in more detail. (Internal link: point this to the contraindications article once published.)

Why equipment and operation matter for safety

Because a hyperbaric chamber is a pressure vessel, its safety depends heavily on how it is built and run. Certified construction, traceable components, proper installation, clear operating instructions, and responsive support all contribute to safe use. This applies whether you are using a soft-shell home chamber or a hard-shell system. Uncertified or imported equipment can be difficult to insure and harder to support, which introduces avoidable risk.

Safe use at home

For home users, the responsibility for safe operation shifts to you, which makes a few habits important. Follow the manufacturer’s instructions on pressure and session length, pressurize and depressurize slowly, equalize your ears as pressure changes, keep ignition sources away, and never use the chamber when unwell or when a contraindication applies. A good supplier provides training so you understand these steps before your first session.

Reducing risk in home use

Most of the safety record for HBOT comes from clinical settings with trained staff. Home use can be safe too, but it shifts responsibility onto the user, so a few practices carry extra weight. Keep the chamber and concentrator maintained according to the schedule, since seals, hoses, and filters all matter to safe operation. Run sessions at the pressure and duration the manufacturer specifies rather than improvising. Keep the area free of ignition sources and well ventilated, given the oxygen-rich environment.

It also helps to set simple rules for yourself. Do not run a session when you are congested or unwell, do not rush the pressurizing phase, and always keep a way to communicate or signal if you are using the chamber alone. Treating the equipment with the respect a pressure vessel deserves is the single biggest factor in keeping home use uneventful.

What to pay attention to across a course

Because effects build over repeated sessions, it is worth noticing how you respond over time rather than judging a single session. Persistent ear discomfort between sessions, ongoing sinus trouble, or any new symptom that concerns you is a reason to pause and seek advice rather than press on. Temporary tiredness after a session is common and usually unremarkable, but anything that feels out of the ordinary is worth taking seriously.

This is also where honest expectations protect you. HBOT for wellbeing is not a treatment for a medical condition, so if you are using a chamber while also managing a health problem, it should never replace the care a clinician provides. If symptoms of an underlying condition change, that is a matter for your doctor, independent of any wellbeing routine. Used sensibly, with sound equipment and realistic expectations, mild home HBOT has a reassuring safety profile, but that profile depends on the user taking the same care a clinic would.

Frequently asked questions

Can hyperbaric oxygen therapy be dangerous?
For approved uses, with proper screening and equipment, serious harm is rare. Risks rise with poor equipment, lack of screening, or use by people for whom it is contraindicated. The most common issue by far is ear pressure, which is usually managed easily.

Is mild HBOT safer than clinical HBOT?
Lower pressures reduce certain higher-pressure risks such as oxygen toxicity, but mild HBOT still requires sound equipment, sensible operation, and awareness of contraindications. Lower pressure is not the same as no precautions.

Should I see a doctor before starting?
If you have any underlying health condition, recent surgery, or are pregnant, speaking to a clinician first is the sensible step. HBOT for wellness is not a replacement for medical care.

What is the single most important safety factor for home use?
Using properly certified, well-supported equipment and following its instructions. With a pressure vessel, the quality and operation of the equipment underpins everything else.

This article is intended as general information and does not constitute medical advice. If you plan on starting HBOT or any other holistic therapies, you should consult a qualified health professional, especially if you have any underlying medical conditions.