A composition and method for promoting neutrophil survival and activation such as the treatment of neutropenia arising as an undesirable side effect of chemotherapy and radiation therapy. A composition containing medium-chain fatty acids, such as capri acid or caprylic acid, or salts or triglycerides thereof, or mono- or diglycerides or other analogues thereof or medium-chain triglycerides (MCT) is administered to a human or animal needing treatment in an amount sufficient to reduce or eliminate neutropenia. The composition is administered in an amount effective to treat the disorder. The methods are also useful in the management of bone narrow transplantation and in the treatment of various neutropenic diseases.
