Lenalidomide is used to treat a certain type of myelodysplastic syndrome (a group of conditions in which the bone marrow produces blood cells that are misshapen and does not produce enough healthy blood cells). Lenalidomide is also used along with dexamethasone to treat people with multiple myeloma (a type of cancer of the bone marrow). It is also used to treat people with multiple myeloma after a hematopoietic stem-cell transplant (HSCT; procedure in which certain blood cells are removed from the body and then returned to the body).