The internet enables access to information and the purchasing of medical products of various quality and legality. Research and regulatory attention have focused on the trafficking of illicit substances, potential physical harms of pharmaceuticals, and possibilities like financial fraud. However, there is far less attention paid to antibiotics and other antimicrobials used to treat infections. With online pharmacies affording greater access, caution around antibiotic use is needed due to the increasing health risks of antimicrobial resistance (AMR). The COVID-19 pandemic has helped to normalise digital healthcare and contactless prescribing, amplifying the need for caution. Little is known of how antibiotics are consumed via digital pharmacy and implications for AMR prevention. To expand insight for AMR prevention policy in Australia and internationally, we use digital ethnographic methods to explore how digital pharmacies function in the context of health advice and policy related to AMR, commonly described as antimicrobial stewardship. We find that digital pharmacy marketplaces constitute 'pastiche medicine'. They curate access to pharmaceutical and information products that emulate biomedical authority combined with emphasis on the 'self-assembly' of healthcare. Pastiche medicine empowers the consumer but borrows biomedical expertise about antibiotics, untethering these goods from critical medicine information, and from AMR prevention strategies. We reflect on the implications of pastiche medicine for AMR policy, what the antibiotics case contributes to wider critical scholarship on digital pharmacy, and how medical humanities research might consider researching online consumption in future.