When adolescents and adults whose alcohol consumption had been screened as hazardous or harmful (most not alcohol dependent) received a web‐based/on‐line intervention or location‐specific electronic screening and/or feedback, their reduction in alcohol consumption was greater than with no/minimal intervention (on average, by approximately 23 g/week [three standard UK units]; moderate‐quality evidence). Moderate‐quality evidence also shows reductions with on‐line/screening interventions in terms of overall frequency of drinking (on average, by 0.16 days drinking/week), frequency of binge drinking (on average, by 0.24 binges/week), and intensity of drinking (on average, by 4.63 g/drinking day). Although the effects are fairly consistent, it is unclear whether these small to modest improvements are sustained over the longer term or result in subsequent reductions in alcohol‐related events, in terms of behavioral or general health.