Myelosuppression or bone marrow suppression is a condition in which bone marrow activity is decreased, resulting in fewer red blood cells, white blood cells, and platelets. Myelosuppression is a side effect of some cancer treatments. When myelosuppression is severe, it is called myeloablation. The phenotype is myelosuppression (EFO_0007053). Also known as: bone marrow suppression.