The Centers for Disease Control and Prevention (CDC) coordinates investigations of multistate foodborne outbreaks. To better inform future communication efforts with the public during these outbreaks, we conducted a qualitative content analysis of comments on multistate foodborne outbreak Facebook posts distributed on the CDC's Facebook page September to December 2018. The CDC created 27 Facebook posts for nine multistate foodborne outbreaks (one to eight posts per outbreak), and 2,612 comments were analyzed. The CDC used two Web tools to deliver outbreak information: food safety alerts (FSAs) and investigation notices (INs). Qualitative analyses were conducted separately for Facebook posts resulting from FSAs and INs. Using an inductive coding approach, we identified nine categories of comments: information sharing (e.g., tagging others), actions (e.g., discarding contaminated food), convictions and beliefs (e.g., food-related preconceived notions), questions (e.g., clarifying outbreak location), emotional responses (e.g., worry), blame (e.g., responsibility for outbreak), food specific (e.g., repackaging ground beef and losing identifying information), promoting another cause (e.g., vaccine hesitancy), and unrelated. No differences were found between FSAs and INs. Facebook users helped further disseminate important outbreak information but identified barriers that prevented them from taking recommended actions. Real-time evaluation of social media during outbreaks provides opportunities to refine messaging and improve communication.