There are 89 included studies. The design of the studies was CBA (Controlled Before and After) (5), CCT (Controlled Clinical Trial) (2), ITS (Interrupted Time Series) (56) and RCT (Randomised Controlled Trial) (26). The 89 studies report 95 interventions with reliable data about at least one outcome. 2 study/studies report/reports 2 interventions and 1 study/studies reports more than 2 interventions... The number of studies by continent is N America (52), Europe (29), Far East (3), S America (3) and Australasia (2)... The aim of the interventions was to optimise therapy either by (a) reducing the amount of antibiotic prescribed where this was considered excessive or (b) increasing the amount of antibiotic prescribed or improving the timing of administration where these were considered sub-optimal. Of the 95 interventions 79 aimed to decrease excessive antibiotic use, 11 aimed to increase effective treatment and 5 aimed to reduce inappropriate antibiotic use but did not distinguish..