Religrast 300mcg Injection 0.5 ml belongs to the class of medicine called ‘hematopoietic agent’ used to treat neutropenia, a lack of certain white blood cells caused by cancer, bone marrow transplant, receiving chemotherapy, bacterial infections or other conditions. Neutropenia is a condition in which the number of neutrophils (a type of white blood cell) in the blood is decreased. White blood cells (neutrophils) protect the body from infections. Without enough neutrophils, the body can not fight off bacteria which increases the risk of many types of infections.