The maintenance of redox homeostasis is critical to the well-being of living tissues. Inhalation of material capable of perturbing the pro-oxidant/antioxidant balance in favour of oxidative stress is likely to lead to an inflammatory reaction in lung tissues. Materials such as ozone and nitrogen oxides are capable of inducing oxidative stress directly. Other materials may instead activate and attract inflammatory cells which generate oxidative stress through superoxide production. The literature supporting these assertions is reviewed and the importance of an understanding of redox homeostasis to the design and interpretation of experiments in cotton dust research is discussed.