Hepatitis B immune globulin is given immediately after exposure to the hepatitis B virus, or within 24 hours of birth for newborns if the mother has hepatitis B. Injection of hepatitis B immunoglobulin is a passive immunization. Immediately after exposure to hepatitis B virus, there is no hepatitis B antibody in the body. Immediately injecting hepatitis B immunoglobulin can prevent the replication of hepatitis B virus in the body, which can enable the body to obtain hepatitis B antibody quickly and clear hepatitis B virus quickly to avoid hepatitis B infection. The earlier the immunoglobulin is injected, the better, to prevent the hepatitis B virus from replicating in the body in large quantities. Pregnant women with hepatitis B, whose newborns are at risk of hepatitis B infection during delivery, should be injected with hepatitis B immunoglobulin as soon as possible within 24 hours after birth to clear any hepatitis B virus that may be present in the body. Hepatitis B immunoglobulin injections may have certain adverse effects, so patients are advised to have the injections under the guidance of a medical professional.