Sterile, as used in general medicine, basically means free of germs. Sterile can also refer to drugs, even though it’s typically used in reference to medical settings like operating rooms and instruments like scalpels. To ensure that the medication remains sterile from the moment it is compounded until it is used, sterile medications are mixed in a sterile environment. Injections, eye drops, and any other medication that circumvents your body’s natural defenses must be administered using this technique.