People who donate granulocytes (infection-fighting white blood cells) for transfusion to patients with severe white cell deficiencies are often given a steroid called dexamethasone and a growth factor called G-CSF the day before donation. These drugs stimulate white cell production, allowing many more cells to be collected than would otherwise be possible. A single dose of G-CSF given to healthy people increases their white cells counts by four to five times the next day.