The pro-inflammatory cytokine interleukin-1 (IL-1) has been proposed as a mediator of the acute neurodegenerative changes that occur following stroke. This is based largely on experimental studies in rodents, in particular the marked reduction in ischemic cell death seen when IL-1 receptor antagonist (IL-1ra) is administered. Mechanisms of IL-1 action remain largely unknown, but they may involve complex effects on many cells including microglia, astrocytes, neurons, and endothelial cells. In light of this, IL-1ra is currently under consideration as a potential treatment for stroke and other neurodegenerative conditions.