Demeclocycline, a chlortetracycline analogue produced by a mutagenised strain of Streptomyces aureofaciens, was first isolated in 1957. Like all tetracyclines, demeclocycline shows broad spectrum antibacterial and antiprotozoan activity and acts by binding to the 30S and 50S ribosomal subunits, blocking protein synthesis. Demeclocycline has been extensively cited in the literature with over 800 references relating almost exclusively to in vivo use.