# Gas as medicine: the case for hydrogen gas as a therapeutic agent for critical illness.
> 重症疾患における水素ガスの医療応用：吸入および水素富化液による多面的保護効果の検討


## Abstract

This review examines the evidence supporting molecular hydrogen gas (HG), delivered by inhalation or as hydrogen-rich fluids, as a protective agent in critical illness. Mechanistically, HG reduces oxidative stress and inflammation while exerting antiapoptotic and mitochondria-supportive effects. Preclinical data indicate improved outcomes across a range of conditions including sepsis, acute lung injury, hepatic and pancreatic injury, cardiac arrest, traumatic injury, acute kidney injury, and brain injury. Human studies conducted across multiple disease states report a favorable safety profile alongside encouraging clinical signals. The author argues that the accessibility and low cost of HG justify evaluation in adequately powered randomized clinical trials focused on critically ill patients.

### Mechanism

HG scavenges reactive oxygen species to reduce oxidative stress, suppresses inflammatory signaling pathways, preserves mitochondrial function, and inhibits apoptotic cell death in critical illness models.

## Bibliographic

- **Authors**: Chawla LS
- **Journal**: Intensive Care Med Exp
- **Year**: 2025 (2025-09-12)
- **PMID**: [40938520](https://pubmed.ncbi.nlm.nih.gov/40938520/)
- **DOI**: [10.1186/s40635-025-00798-w](https://doi.org/10.1186/s40635-025-00798-w)
- **PMC**: [PMC12431974](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12431974/)
- **Study type**: review
- **Delivery route**: mixed routes
- **Effect reported**: not assessed

## Delivery context

This study combines multiple delivery routes. As a general principle, the most efficient route for routine hydrogen intake is inhalation. Inhalation carries explosion risk (empirical LFL of 10%; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

## Safety notes

This study combines multiple delivery routes. As a general principle, the most efficient route for routine hydrogen intake is inhalation. Inhalation carries explosion risk (empirical LFL of 10%; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 40938520. https://h2-papers.org/en/papers/40938520
> **Source**: PubMed PMID [40938520](https://pubmed.ncbi.nlm.nih.gov/40938520/)