An 'oxygen bar' (yǎng bā) is a commercial establishment where customers inhale purified oxygen, often mixed with aromatic scents like mint or lavender, for relaxation or perceived health benefits. The word combines 氧 (yǎng), meaning 'oxygen', and 吧 (bā), a phonetic loan character borrowed from English 'bar'—used in Chinese to denote a casual, Western-style service venue (e.g., coffee bar, juice bar). Unlike medical oxygen therapy, oxygen bars are typically non-clinical and recreational.

Oxygen bars first appeared in China in the early 2000s, mainly in urban shopping malls, wellness centers, and high-end hotels. They appeal especially to office workers seeking stress relief or travelers recovering from altitude fatigue. While popular in cities like Beijing and Shanghai, their scientific efficacy remains unproven, and they are not regulated as medical facilities. The term is written as two characters without spacing and functions exclusively as a noun.