Background: This study reviewed Twitter status updates mentioning "antibiotic(s)'' to determine overarching categories and explore evidence of misunderstanding or misuse of antibiotics. Methods: One thousand Twitter status updates mentioning antibiotic(s) were randomly selected for content analysis and categorization. To explore cases of potential misunderstanding or misuse, these status updates were mined for co-occurrence of the following terms: "cold + antibiotic(s),'' "extra + antibiotic(s),'' "flu + antibiotic(s),'' "leftover + antibiotic(s),'' and "share + antibiotic( s)'' and reviewed to confirm evidence of misuse or misunderstanding. Results: Of the 1000 status updates, 971 were categorized into 11 groups: general use (n = 289), advice/information (n = 157), side effects/negative reactions (n = 113), diagnosis (n = 102), resistance (n = 92), misunderstanding and/or misuse (n = 55), positive reactions (n = 48), animals (n = 46), other (n = 42), wanting/needing (n = 19), and cost (n = 8). Cases of misunderstanding or abuse were identified for the following combinations: "flu + antibiotic(s)'' (n = 345), "cold + antibiotic(s)'' (n = 302), "leftover + antibiotic( s)'' (n = 23), "share + antibiotic(s)'' (n = 10), and "extra + antibiotic(s)'' (n = 7). Conclusion: Social media sites offer means of health information sharing. Further study is warranted to explore how such networks may provide a venue to identify misuse or misunderstanding of antibiotics, promote positive behavior change, disseminate valid information, and explore how such tools can be used to gather real-time health data.