The objective of most modern drug delivery strategies is to maximize the effectiveness of drug molecules at diseased tissue and to minimize their effects in healthy ones. This is most often achieved using (bio-)synthetic carrier systems that release the drug at the target location. One emerging strategy to achieve this is to destabilize carriers and release therapeutics using natural redox gradients in the body or associated with disease. The body, however, is composed of numerous microenvironments whose redox homeostasis, as well as its dysregulation due to disease, is complex. The original article and authoritative reviews that constitute this Forum discuss some of the particular redox features associated with diseases and present an overview of how, chemically, redox-responsive drug delivery carriers can be designed to respond to these opportunities.