Simultaneous expansion of the Internet and increased globalisation of the pharmaceutical industry have meant medication can be accessed transnationally from both legal and illicit sources. This has coincided with the rise of substandard and falsified medicines (SFMs) online. These products fail to meet regulatory or quality standards and/or are constituted with substandard ingredients, causing undesired pharmacological effects, including possible injury and death. This review aimed to identify original research studies that examined characteristics of SFM online sales, attitudes towards purchasing medicines online and strategies to address this drug safety challenge. Keywords of ‘Substandard’ and ‘Falsified’/‘Counterfeit’ and ‘Medicines’/‘Drugs’ and ‘Online’/‘Internet’ were searched using Web of Knowledge and PubMed databases. Resulting literature, which satisfied the study’s inclusion criteria, was included in the review, and the findings from each paper were assessed. From an initial 185 literature articles, 7 were eligible according to the inclusion criteria to be reviewed. These articles identified studies testing SFMs purchased online, surveys of attitudes and knowledge about SFMs online, and website content analysis to detect illegal online sales. Challenges identified were lack of knowledge and awareness among consumers and physicians, in addition to the use of direct-to-consumer-advertising, via Internet platforms and social media, providing easy access to SFMs. Despite this, medicine authentication technology, website verification approaches and new detection methods were identified as potential solutions specific to online SFM sales. To address online sales of SFMs, more robust research, greater awareness/educational programmes, analytical detection methods and more stringent online global governance are required.