Health professionals communicate with each other about medication information using different forms of documentation. This article explores knowledge and power relations surrounding medication information exchanged through documentation among nurses, doctors and pharmacists. Ethnographic fieldwork was conducted in 2010 in two medical wards of a metropolitan hospital in Australia. Data collection methods included participant observations, field interviews, video‐recordings, document retrieval and video reflexive focus groups. A critical discourse analytic framework was used to guide data analysis. The written medication chart was the (...) main means of communicating medication decisions from doctors to nurses as compared to verbal communication. Nurses positioned themselves as auditors of the medication chart and scrutinised medical prescribing to maintain the discourse of patient safety. Pharmacists utilised the discourse of scientific judgement to guide their decision‐making on the necessity of verbal communication with nurses and doctors. Targeted interdisciplinary meetings involving nurses, doctors and pharmacists should be organised in ward settings to discuss the importance of having documented medication information conveyed verbally across different disciplines. Health professionals should be encouraged to proactively seek out each other to relay changes in medication regimens and treatment goals. (shrink)