Fourteen-membered rings

Erythromycin (sometimes abbreviated ETM in reports) is an antibiotic used for the treatment of a number of bacterial infections. This includes respiratory tract infections, skin infections, chlamydia infections, pelvic inflammatory disease, and syphilis. It may also be used during pregnancy to prevent Group B streptococcal infection in the newborn, and to improve delayed stomach emptying. It can be given intravenously and by mouth. An eye ointment is routinely recommended after delivery to prevent eye infections in the newborn.

Clarithromycin, sold under the brand name Biaxin among others, is an antibiotic used to treat various bacterial infections. This includes strep throat, pneumonia, skin infections, H. pylori infection, and Lyme disease. Clarithromycin can be taken by mouth as a tablet or liquid or can be infused intravenously.

Roxithromycin is a semi-synthetic macrolide antibiotic used to treat respiratory tract, urinary and soft tissue infections. It is a derivative of erythromycin - comprising the same 14-membered lactone ring - with an oxime-based side chain attached to the macrolide ring.

Telithromycin is the first ketolide antibiotic to enter clinical use and is sold under the brand name of Ketek. It is used to treat community acquired pneumonia of mild to moderate severity. After significant safety concerns, the US Food and Drug Administration sharply curtailed the approved uses of the drug in early 2007.

Troleandomycin (TAO for short) is a macrolide antibiotic. It was sold in Italy (branded Triocetin) and Turkey (branded Tekmisin). It is no longer sold in Italy as of 2018.

Dirithromycin is a macrolide glycopeptide antibiotic.

Oleandomycin is a macrolide antibiotic. It is synthesized from strains of Streptomyces antibioticus. It is weaker than erythromycin.

Cethromycin, trade name Restanza (initially known as ABT-773) is a ketolide antibiotic undergoing research for the treatment of community acquired pneumonia (CAP) and for the prevention of post-exposure inhalational anthrax, and was given an "orphan drug" status for this indication. Originally discovered and developed by Abbott, it was acquired by Advanced Life Sciences Inc. for further development.

thumb|right|Telithromycin Ketolides are antibiotics belonging to the macrolide group. Ketolides are derived from erythromycin by substituting the cladinose sugar with a keto-group and attaching a cyclic carbamate group in the lactone ring. These modifications give ketolides much broader spectrum than other macrolides. Moreover, ketolides are effective against macrolide-resistant bacteria, due to their ability to bind at two sites at the bacterial ribosome as well as having a structural modification that makes them poor substrates for efflux-pump mediated resistance.