Prostaglandin E1 is primarily used in medical settings for its vasodilatory properties. It is often administered to treat erectile dysfunction by relaxing smooth muscle tissue and increasing blood flow. In neonatal care, it is used to keep the ductus arteriosus open in newborns with congenital heart defects, allowing for proper blood circulation until surgical correction can be performed. Additionally, it is employed in the treatment of peripheral vascular diseases to improve blood flow and reduce symptoms like pain and ulcers. Its anti-inflammatory and immunomodulatory effects also make it useful in managing certain autoimmune conditions.