Background Online medical consultation has recently become a more and more popular alternative venue for healthcare. It allows patients and caregivers to discuss their health problems and symptoms with qualified medical health professionals via the Internet. Objective This study investigates the questions posted on an asynchronous online medical consultation website, Taiwan eDoctor. Five research themes are explored: (1) length of questions, (2) moment of seeking consultation, (3) strategies of communicating chief complaints, (4) purpose of seeking consultation and (5) identity disclosure. Methods Data collection was conducted by randomly selecting 50 resolved consultation Q&As for each of 24 medical specialties, resulting in a total of 1200 entries in the primary data set. Data analysis was conducted qualitatively and quantitatively. Results Average length of questions was 161.21 words. Online medical consultation was sought when healthy, healthy but not robust, when suspicious of illness, when diagnosed as ill and during treatment/recovery. In communicating chief complaints, consultation seekers were engaged in contextual, focal or emotional communication styles. Nine distinct purposes to seek online consultation were identified and can be broadly interpreted as intellectual, social and emotional. The finding also suggests that more than two‐third of questions were asked for by the patients themselves. Conclusion Through content analysis of questions posted on an online medical consultation website, this study characterises communication patterns during the health information seeking process. These findings can help guide the design of more effective patient‐centred online medical consultation services.