Linton, A.H., Hinton, M.H.&Al‐Challaby, Z.A.M. Monitoring for antibiotic resistance in enterococci consequent upon feeding growth promoters active against Gram‐positive bacteria.J. vet. Pharmacol. Therap.8, 62–70.Commercial chicken and pig farms, using different growth promoters, were monitored for enterococci resistant to a range of antibacterial agents. Due to inconsistent findings attributed to uncontrollable factors, chickens kept under experimental conditions were also studied. A total of 4216 isolates from all the surveys were examined. Resistant isolates were often encountered, even in control groups, suggesting complex population changes not necessarily solely connected with the influence of the growth promoters. It was concluded that comprehensive methods for differentiating strains are necessary to unravel this problem.A. H. Linton, Department of Microbiology, University of Bristol, Bristol, Avon BS8 ITD, En