Colony-Stimulating Factors (CSFs) are a group of proteins that play a crucial role in the production and regulation of blood cells. They stimulate the bone marrow to produce specific types of blood cells, such as white blood cells, which are essential for the immune system. CSFs help the body respond to infections and other diseases by increasing the number of these cells. There are several types of CSFs, including granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF). These factors are often used in medical treatments, especially for patients undergoing chemotherapy, to boost their blood cell counts and reduce the risk of infections.