Agar is a mucilaginous complex sulfated polymer (chain) of galactose units, extracted from red algae(see Algae)such as Gelidium cartilagineum. Since agar has the ability to form a gel-like consistency, it is used as stabilisers in many products. For example, agar can be used to form the medium in which bacteria grow. Hot liquid agar is poured into plastic dishes and when it hardens (gels), bacteria can be swabbed onto this medium and grown. This is important in medicine, where grown bacteria can be further identified in regards to diagosing a particular bacterial infection in a patient.