The packing list for an HBOT session is short. Most of what people forget is on the "do not bring" side, and almost all of those rules trace back to chamber fire safety. We pulled the FDA fire-safety guidance and UHMS clinical practice notes to summarize.
The FDA has cleared HBOT for 13 set uses (FDA 2021). The packing rules below apply to all HBOT, both FDA-cleared and off-label.
Read the rules once, follow them, and your sessions will be uneventful.
Why fire safety drives the rules
The chamber atmosphere during HBOT is 100% oxygen at 2.0-2.4 ATA. This is a fire-prone environment (Sheffield & Desautels 1997).
The FDA issued a 2021 letter to health care providers on chamber fire safety after several incidents at non-medical sites. The letter spelled out the materials and behaviors that cause fires.
Most chamber fires start with a static spark or electronic short circuit in oxygen-rich air. Once started, fires in HBOT chambers spread fast and are nearly impossible to extinguish from inside.
UHMS-vetted hospital programs running Sechrist Industries or Perry Baromedical chambers have strict pre-session checks. Newer wellness operators may be less rigorous.
What to bring
The list is short.
Cotton clothing or a hospital gown. Most clinics provide a 100% cotton gown. If you bring your own clothes, cotton sweats and a cotton T-shirt are safe.
Avoid synthetic fabrics (polyester, nylon, rayon) — they have lower ignition temperatures in high-oxygen air (UHMS Indications Manual 2019).
Plain water bottle. Most chambers allow water during sessions. Standard plastic water bottles are fine.
Eyeglasses, not contacts. Contact lenses can trap small oxygen bubbles against the eye during pressure changes (Simon & Bradley 1978). Most programs allow glasses; some require them off.
Bring a case.
Hearing aids or assistive devices — only if the program clears them. Most modern hearing aids are electronic and not chamber-safe. Ask in advance.
Your drug list and medical history. Have a written list of current prescriptions, recent chemo, and any prior bleomycin exposure. See our HBOT and drug issues article.
Something to occupy yourself. A book or magazine — paper only, no electronics. Most clinics provide TV through an external monitor visible through the chamber window.
For diabetic patients, a small snack and glucose meter. HBOT lowers blood glucose. See our HBOT and nutrition pre-session guidelines.
What to leave at home
The "do not bring" list is longer.
Electronics. Cell phones, smartwatches, fitness trackers, e-readers, tablets — all banned in the chamber. Static buildup and battery shorts in 100% oxygen are real fire risks.
Hand warmers and self-heating products. Anything that generates heat through chemical reaction is a fire risk.
Lighters, matches, vapes, e-cigarettes. These are obvious but people still try.
Oil-based hair products. Pomade, mousse, hairspray, leave-in conditioners with oil bases. Wash hair plain on session days or use water-based products only.
Cosmetics with oil or alcohol bases. Lipstick, foundation, eye makeup. Most clinics require makeup-free for chamber sessions.
Nail polish. Some clinics ask for it off. Acrylic nails are usually fine.
Jewelry, especially metal jewelry. Static buildup risk. Most programs ask for all jewelry off.
Perfume, cologne, aftershave. Alcohol bases are fire risks.
Lotion or sunscreen applied within hours of the session. Most products contain alcohol or oil.
Hot patches (Lidoderm, nicotine patches, hormone patches) — some are chamber-safe, some are not. Ask the program in advance.
Special note on petroleum products
Petroleum jelly (Vaseline), petroleum-based ointments, and many topical creams are fire-prone in high-oxygen air. Wash off any topical products before the session.
For wound-care patients with prescribed topical drugs on the wound itself, the hyperbaric staff will guide you. Some products are cleared for chamber use; some are not. The treatment team will swap dressings as needed.
For more on chamber safety, see our HBOT safety checklist.
Eye protection: contact lenses vs glasses
The contact lens question comes up often. The published case reports of contact-lens problems in HBOT are limited. Some hyperbaric programs allow soft contact lenses; many do not.
The safe default is glasses. Bring a case so you can take them off during sleep periods in long sessions.
If you must wear contacts, ask the hyperbaric doctor in advance. Hard contact lenses are more concerning than soft.
Ear protection during decompression
The ears equalize automatically during decompression at session end. No earplugs, no maneuvers needed.
If you have known ear problems, the team may give you a saline spray before sessions. Pseudoephedrine 30-60 minutes before can help some patients with mild Eustachian tube issues — but discuss with the doctor first.
For more, see our how to equalize your ears in a hyperbaric chamber guide.
Bathroom considerations
A 60-90 minute session is the standard duration. You will not be able to leave the chamber mid-session.
Use the bathroom right before the session. Some patients ask about urinary catheters for inpatient HBOT — those are arranged by the hospital team.
Hydrate steadily during the day before. Show up not over-hydrated and not dehydrated. See our nutrition pre-session guidelines.
What the clinic will provide
Most UHMS-vetted hospital programs provide:
- A 100% cotton hospital gown
- A pillow and blanket inside the chamber
- An intercom or communication system to staff
- Water in a clinic-approved bottle
- A TV system viewable through the chamber window
- The session monitoring equipment (pulse oximeter, ECG leads, etc.)
Wellness clinics at sites running OxyHealth or Summit to Sea soft-shell chambers may have less equipment. Restore Hyper Wellness sites typically offer basic gown, water, and music. Aviv Clinics provides a more premium amenity setup as part of its higher-priced package. See Aviv Clinics evidence vs. marketing for the marketing-vs-evidence breakdown.
Children and pediatric sessions
Children doing HBOT may bring a paper book or a stuffed animal (no electronics inside, no batteries). Parents sometimes attend the first session via multiplace chamber if available.
For more on pediatric HBOT, see our pediatric HBOT chambers overview.
Day-of timing
A typical HBOT visit looks like this:
- Arrive 30 minutes before scheduled session time. Check-in, drug review for early sessions, change into gown.
- Pre-session ear-clearing practice if needed.
- Blood glucose check for diabetic patients.
- Compression: 10-15 minutes as the chamber reaches treatment pressure.
- Treatment phase: 60-90 minutes at full pressure.
- Decompression: 10-15 minutes back to surface pressure.
- Post-session monitoring: 10-15 minutes as you stabilize.
Total visit time: typically 2 to 2.5 hours.
A note on session length and protocols
The standard FDA-cleared HBOT protocols run 30-40 sessions over 6-8 weeks. Acute uses (CO poisoning, severe burns) compress this calendar. Off-label anti-aging protocols at premium clinics extend to 60+ sessions. See the carbon monoxide poisoning evidence atlas for the full study-by-study evidence breakdown.
The pre-session packing rules are the same regardless of protocol length. See our HBOT frequency article for more on protocol differences.
What to ask in advance
Before your first session, the clinic should provide a written pre-session checklist. If they do not, ask:
- What clothing do you provide vs what should I bring?
- Are contact lenses allowed?
- May I bring water and a snack?
- May I bring a book or magazine?
- What hair and skin products are restricted?
- How long is the typical visit?
- How early should I arrive for the first session?
The answers should be clear. A clinic that cannot answer these basics is concerning.
For more on choosing a clinic, see our how to find a legitimate HBOT clinic guide.
Bottom line
Bring: cotton clothes (or use the clinic's gown), plain water, glasses, your drug list, something to read.
Leave: all electronics, anything that burns, all oil or alcohol products, jewelry, perfume, makeup.
Most clinics provide a written pre-session checklist. Read it, follow it, and your sessions will go smoothly.
Related Reading
- How to equalize your ears in a hyperbaric chamber
- HBOT and nutrition pre-session guidelines
- HBOT and medication interactions to know
- HBOT safety checklist: red flags and what to verify
- How to find a legitimate HBOT clinic near you
Frequently asked questions
What should I wear to HBOT?
100% cotton clothing, or use the clinic's hospital gown. Avoid synthetic fabrics like polyester, nylon, and rayon — they have lower ignition points in high-oxygen air.
Can I bring my phone into the chamber?
No. Cell phones, smartwatches, and all other electronics are banned because of fire risk in 100% oxygen at chamber pressure.
Are contact lenses safe in HBOT?
Many programs do not allow contact lenses during HBOT due to oxygen bubble trapping risk. Bring glasses instead. If you must wear contacts, ask the hyperbaric doctor in advance.
Can I wear makeup?
Most clinics require makeup-free for chamber sessions. Cosmetics often contain oil or alcohol bases that are fire risks in 100% oxygen.
How long is a typical HBOT visit?
Total visit time is usually 2 to 2.5 hours: 30 minutes for check-in, 10-15 minutes compression, 60-90 minutes at treatment pressure, 10-15 minutes decompression, and 10-15 minutes post-session monitoring.
Medical disclaimer: This article is informational and does not constitute medical advice. HBOT carries real risks including ear barotrauma, oxygen toxicity, and chamber fire. The pre-session restrictions exist for fire safety. Follow your clinic's written pre-session checklist. Discuss any HBOT plan with a doctor trained in undersea and hyperbaric medicine before starting.
-- The HBOT Finder Team