Several disorders can appear to be infections when actually they are not. Conversely, certain infectious diseases can manifest themselves as something other than infection. These unwittingly mistaken diagnoses segue into misguided therapy-misuse of antibiotics in particular-and consequently fail to improve. These disorders have been described separately. Grouping them together draws attention to their importance in an infectious disease differential diagnosis. This article systematically assembles and briefly discusses some of these infectious-appearing diseases.