Hyperbaric oxygen therapy (HBOT) is a proven adjunct for a short list of serious infections, not a general antibiotic substitute. Its clearest use is gas gangrene, where adding HBOT to surgery and antibiotics is associated with amputation rates near 18%, compared with 50% or higher historically.2 HBOT is FDA-cleared for clostridial myonecrosis and refractory osteomyelitis, and it works by raising tissue oxygen high enough to kill anaerobes, power immune cells, and restore antibiotic efficacy.
Which Infections Is HBOT Actually Cleared to Treat?
HBOT has established, guideline-recognized roles in a handful of infections where low tissue oxygen is central to the problem. The Undersea and Hyperbaric Medical Society (UHMS) lists clostridial myonecrosis, refractory osteomyelitis, and necrotizing soft tissue infection among its approved indications.1 Everything below rests on that framing.
HBOT by Infection Type
| Infection | HBOT role | Evidence |
|---|---|---|
| Gas gangrene (clostridial myonecrosis) | FDA-cleared adjunct to surgery + antibiotics | Strong |
| Refractory osteomyelitis | FDA-cleared adjunct after debridement | Moderate-Strong |
| Necrotizing fasciitis | Adjunct to emergency surgery | Moderate, retrospective |
| Diabetic foot infection | Adjunct in ischemic, non-healing cases | Moderate |
| Chronic Lyme disease | Not recommended | Limited / none |
Gas Gangrene (Clostridial Myonecrosis)
This is HBOT’s clearest infection indication. Gas gangrene is a rapidly progressive, life-threatening infection caused by Clostridium perfringens that destroys muscle and produces gas in tissue. Treatment is emergency surgical debridement combined with HBOT and antibiotics. HBOT is FDA-cleared here and is a standard-of-care adjunct where facilities exist.
The mechanism is direct. Anaerobic Clostridium bacteria are inhibited by the high oxygen tensions HBOT produces, which slows spread while surgery removes destroyed tissue. A tissue oxygen level around 250 mmHg is needed to halt alpha-toxin production, a level reachable only through HBOT.2
Amputation rate for gas gangrene treated with HBOT plus surgery and antibiotics, versus 50% or higher without HBOT.
Kaide & Khandelwal, 2008
Chronic Osteomyelitis
Chronic bone infection involves bacteria embedded in avascular, ischemic bone that resists both antibiotics and immune clearance. HBOT is an FDA-cleared adjunct for refractory osteomyelitis, used after surgical debridement to improve tissue oxygenation, enhance antibiotic efficacy, and support bone healing. Protocols typically run 40 to 60 sessions following definitive surgery. Our bone healing and HBOT article covers this in detail, and refractory osteomyelitis is among the chronic conditions treated with hyperbaric oxygen.
Necrotizing Fasciitis
Necrotizing fasciitis (“flesh-eating” infection) spreads rapidly along fascial planes and can be caused by a mix of aerobic and anaerobic organisms. The treatment is emergency surgical debridement, often extensive. HBOT is used as an adjunct in many centers to limit anaerobic spread, support immune function, and aid healing of the surgical wound.3 It is not a substitute for emergency surgery.
A 2022 study of 192 necrotizing fasciitis and Fournier’s gangrene patients found that HBOT recipients had survival comparable to non-recipients despite presenting with more severe disease, including more frequent sepsis and more surgical debridements.5 The evidence base here is retrospective, drawn from centers that happen to have chambers, which is one reason HBOT remains an adjunct rather than a first-line intervention.
Tissue oxygen tension required to halt clostridial alpha-toxin production, achievable only with hyperbaric oxygen.
Kaide & Khandelwal, 2008
Diabetic Foot Infections
Diabetic foot infections complicate foot ulcers and are a leading cause of amputation. Impaired circulation, neuropathy, and immune dysfunction combine to make infections hard to clear and wounds slow to heal. HBOT is used as an adjunct in severe, ischemic diabetic foot infections. In a randomized trial, HBOT improved healing of chronic diabetic foot ulcers compared with standard care.4 Our diabetes and HBOT and wound healing articles cover this population in full.
How Does HBOT Kill Bacteria?
HBOT does not act like an antibiotic. It works by flooding infected tissue with oxygen, which is directly toxic to some bacteria, powers the immune cells that kill others, and restores the oxygen-dependent action of certain antibiotics.
Direct Toxicity to Anaerobic Bacteria
Many dangerous soft tissue infections are caused by anaerobes: organisms that do not require oxygen and are actively harmed by it. Clostridium perfringens, Bacteroides, and similar species are killed or inhibited at high oxygen tensions. At the partial pressures achieved in a chamber (up to roughly 1,500 mmHg at 2.0 ATA), anaerobic growth is suppressed in a way antibiotics alone may not achieve in poorly perfused tissue.1
Enhanced White Blood Cell Function
Neutrophils and macrophages kill bacteria largely through oxidative killing, generating reactive oxygen species that destroy bacterial cell walls. This process is oxygen-dependent, and in the ischemic tissue where serious infections take hold, that killing capacity is impaired. HBOT restores it, letting immune cells clear infection more effectively.2
Improved Antibiotic Penetration
Antibiotics work better in well-oxygenated tissue. Aminoglycosides (gentamicin, tobramycin) require oxygen-driven active transport to enter bacterial cells, and their efficacy drops sharply in hypoxic environments. By oxygenating infected, ischemic areas, HBOT restores antibiotic activity where it had failed. This synergy matters most in chronic osteomyelitis and diabetic foot infections, where appropriate serum drug levels still fail to work in oxygen-starved local tissue.2
Biofilm Disruption
Biofilm-forming bacteria encase themselves in a protective matrix that resists antibiotics and immune clearance. High oxygen tensions disrupt biofilm formation in some species and improve antibiotic penetration into biofilm-protected communities. This is an active area of preclinical investigation rather than settled clinical practice.
Does HBOT Help Antibiotic-Resistant Infections?
HBOT’s effect against anaerobes is independent of antibiotic resistance, because it works through direct oxygen toxicity rather than the pathways antibiotics use. For aerobic resistant organisms such as MRSA, the effect is indirect: HBOT improves immune killing and antibiotic delivery rather than killing bacteria outright. Combined with appropriate antibiotics and surgery, that improved local environment may aid outcomes in resistant infections, though HBOT is never a standalone answer to resistance.
Which Infections Does HBOT Not Treat?
Common infections have no established HBOT evidence base. Pneumonia, urinary tract infections, routine skin infections that respond to antibiotics, and viral infections do not benefit. HBOT is not an antibiotic substitute and is not effective against viral pathogens.
Chronic Lyme Disease
One of the more aggressively marketed claims involves chronic or post-treatment Lyme disease. The theoretical basis is Borrelia burgdorferi‘s relative oxygen sensitivity, but the evidence does not support the practice. A single small 2014 case report suggested benefit; it has not been replicated, and mainstream infectious disease guidelines do not recommend HBOT for Lyme disease. The claims exceed the evidence by a wide margin.
Routine Infections
Using HBOT for everyday infections is neither evidence-based nor clinically appropriate. The legitimate indications share a common thread: tissue that is ischemic, anaerobic, or otherwise beyond the reach of antibiotics alone. Where that thread is absent, so is the rationale. For the full list of established uses, see our guide to FDA-cleared HBOT indications.
Frequently Asked Questions
Does HBOT work against antibiotic-resistant bacteria?
Against anaerobic bacteria, HBOT works through direct oxygen toxicity, so its effect is independent of antibiotic resistance. Against aerobic resistant organisms such as MRSA, the effect is indirect: HBOT improves immune killing and antibiotic penetration rather than killing bacteria directly (Kaide & Khandelwal, 2008). Combined with appropriate antibiotics and surgery, that improved local environment may improve outcomes, but HBOT alone does not overcome resistance.
How quickly must HBOT be started for gas gangrene?
Emergency surgery is the immediate priority. HBOT should follow as soon as possible after initial debridement. In centers with hyperbaric facilities, first treatment is typically within hours of surgery. Timing is critical: every hour of delay allows clostridial toxin production to continue and the infection to spread, which is why halting alpha-toxin production at high tissue oxygen matters (Kaide & Khandelwal, 2008).
Can HBOT prevent infection after surgery?
HBOT enhances the oxidative killing capacity of immune cells in the early post-operative period, and some data suggest reduced infection rates in specific populations such as colorectal and diabetic surgical patients (UHMS, 2020). This is not a standard clinical use. HBOT is not recommended as routine infection prophylaxis for most surgical procedures, and it is reserved for defined indications rather than general prevention.
Does HBOT help with fungal infections?
Evidence is limited. Certain molds and fungi have aerobic metabolic requirements that high oxygen tensions might disrupt, and HBOT is sometimes used adjunctively in aggressive fungal infections like mucormycosis alongside surgery and antifungals. It is not an established standalone treatment for fungal infections, and current guidelines do not recommend it in that role.
Sources
- Undersea and Hyperbaric Medical Society. “HBO Therapy Indications, 13th Edition,” 2020. UHMS
- Kaide CG, Khandelwal S. “Hyperbaric Oxygen: Applications in Infectious Disease.” Emerg Med Clin North Am, 2008. 10.1016/j.emc.2008.01.005
- Jallali N, Withey S, Butler PE. “Hyperbaric oxygen as adjuvant therapy in the management of necrotizing fasciitis.” Am J Surg, 2005. 10.1016/j.amjsurg.2005.01.012
- Löndahl M, Katzman P, Nilsson A, Hammarlund C. “Hyperbaric oxygen therapy facilitates healing of chronic foot ulcers in patients with diabetes.” Diabetes Care, 2010. 10.2337/dc09-1754
- Mladenov A, et al. “Outcome of necrotizing fasciitis and Fournier’s gangrene with and without hyperbaric oxygen therapy.” World J Emerg Surg, 2022. PMC9356491
Medical Disclaimer
The content on BaricBoost.com is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
Author
Seph Fontane Pennock is the founder of BaricBoost.com and Regenerated.com, a clinic directory for regenerative medicine serving 10,000+ providers across the United States. He previously built and sold PositivePsychology.com, which grew to 19 million users and became the largest evidence-based positive psychology resource on the web. Seph brings direct experience as an HBOT patient, having completed protocols at clinics across three continents while navigating mold illness, systemic inflammation, and autoimmune conditions. His treatment journey includes hyperbaric oxygen therapy, peptide protocols, NAD+ therapy, and consultations with specialists from Dubai to Cape Town to Mexico. This combination of entrepreneurial track record and lived patient experience shapes everything published on BaricBoost.com. Every article is grounded in peer-reviewed research, informed by real clinical encounters, and written for patients making high-stakes treatment decisions. Seph's focus is on bringing transparency, scientific rigor, and practical guidance to the hyperbaric oxygen therapy space.
