Frastim 300mcg Injection is used to prevent infections after chemotherapy. It is a growth factor that stimulates the bone marrow to produce white blood cells. These cells protect the body against infections. Frastim 300mcg Injection is given as an injection by a qualified medical professional. You should continue to take as long as your doctor advises for it. The duration of treatment varies according to your need and response to treatment. You might be asked to get regular tests done to check the number of blood cells in your blood and your bone density level while you are taking this medicine. The most common side effects of this medicine include bone pain, weakness, headache, and rash. Other than this, pain or redness at the site of injection is common. But, inform your doctor if you notice a lump, swelling, or bruising that does not go away. It might not prevent you from all kinds of infection, hence inform your doctor if you notice fever, chills, rash, sore throat, and swelling around the face or neck. Many other medicines can affect, or be affected by, this medicine so let your healthcare team know all medications you are using. This medicine is not recommended during pregnancy or while breastfeeding. The use of effective contraception by both males and females during treatment is important to avoid pregnancy.