This study used a content analysis to compare four types of popular health-related accounts on Twitter and on Sina Weibo. Individual Weibo accounts published posts more frequently than any other accounts. An average individual Weibo post also received the greatest number of reposts and favorites. This suggests a great influence of individual Weibo accounts in the dissemination of health-related information, especially about health topics such as body fitness, psychology, and beauty and cosmetics. Among four types of accounts on Weibo, individual Weibo accounts differed most from government Weibo accounts in post themes, with the former focusing on health topics, and the latter focusing on health tips about daily life. In comparison, individual Twitter accounts differed most from association Twitter posts, as the former focused on health tips about daily life, whereas the latter focused on health-related news. Other types of accounts on the two microblogs focused on public relations and promotion. In general, Twitter accounts used interactive features more frequently than Weibo accounts. All types of Twitter accounts except association accounts posted proportionally more posts with hashtags or uniform resource locators (URLs) than their Weibo counterparts. Government and hospital Twitter accounts posted proportionally more posts with a mention than their Weibo counterparts. Finally, each type of Weibo accounts published a greater proportion of posts with attached pictures than their Twitter counterparts. Individual Weibo accounts used videos more often than other types of accounts.