© Springer Science+Business Media, LLC, part of Springer Nature 2019. Often in redox biology experiments there is a need to add compounds which impinge on the redox of the cellular environment cell. Such compounds may include reactive oxygen species (ROS), such as hydrogen peroxide (H2O2), reactive nitrogen species such as nitric oxide (NO), hydrogen sulfide (H2S), or even hydrogen gas (H2). It is not always easy or obvious how such compounds should be used. Gases may be supplied and used in the gaseous form, but this is often not convenient. Alternative methods may involve donor molecules that release into solution the relevant compound, but the actual compound released needs to be considered, along with the kinetics of that release and the by-products that might be remain. Therefore, the method of delivery of redox active compounds needs to have careful consideration before more complex experiments are undertaken. This chapter covers some of the more common methods employed and discusses some of the pros and cons of such methods.