Cognitive deficits following ischemic stroke are common and debilitating, even in the relatively few patients who are treated expeditiously so that clots are removed or dissolved rapidly and cerebral blood flow restored. A new study demonstrates that intracerebral injection of bone-marrow-derived mesenchymal stem cells (BSCs) reduces cognitive deficits produced by temporary occlusion of cerebral blood vessels in a rat model of stroke, suggesting that BSCs may offer a new approach for reducing post-stroke cognitive dysfunction.