Amoxicillin/clavulanic acid, also known as co-amoxiclav or amox-clav, sold under the brand name Augmentin, among others, is an antibiotic medication used for the treatment of a number of bacterial infections.

[5] It is specifically used for otitis media, streptococcal pharyngitis, pneumonia, cellulitis, urinary tract infections, and animal bites.

[14][15] It is active against UTIs caused by Staphylococcus saprophyticus, Enterococci (e.g., Enterococcus faecalis), Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis.

[15] The drug is not effective against Pseudomonas aeruginosa, Morganella morganii, or Providencia stuartii, nor against AmpC β-lactamase- and ESBL-producing Gram-negative bacteria or carbapenem-resistant Enterobacteriaceae (CRE).

[14] In a large high-quality randomized controlled trial of amoxicillin/clavulanic acid for UTI in 370 women, early and late clinical cure rates were 79% and 58%, respectively.

[14][16] A 2012 network meta-analysis of antibiotics for uncomplicated UTIs found that it was less effective than all other assessed agents, including trimethoprim/sulfamethoxazole, nitrofurantoin, fosfomycin, fluoroquinolones (ciprofloxacin, norfloxacin, and gatifloxacin), and pivmecillinam.

Its efficacy is attributed not to the amoxicillin component, but to the protective action of clavulanic acid over meropenem against beta-lactamase produced by the mycobacteria.

As with all antimicrobial agents, antibiotic-associated diarrhea due to Clostridioides difficile infection—sometimes leading to pseudomembranous colitis—may occur during or after treatment with amoxicillin/clavulanic acid.

In addition to its β-lactamase inhibition, clavulanic acid shows central nervous system actions and effects and has been studied in the potential treatment of various psychiatric and neurological disorders.

[citation needed] Amoxicillin/clavulanic acid is used in numerous animals for a variety of conditions: Bacterial antibiotic resistance is a growing problem in veterinary medicine.