macrolides represent the 10-15% of the world-wide market of oral antibiotics. they are one of the safer groups of antibiotics, being the severe adverse reactions very rare. they can produce gastrointestinal reactions, hepatotoxicity and ototoxicity. the psychiatric reactions are found sporadically among the adverse effects. cases reported to the fda showed that clarithromycin and ciprofloxacin are the most frequent antibiotics associated with the development of mania. the syndrome has been termed antibiomania. we present three clinical cases seen in a primary care office in the last year with similar pictures of hyperactivity and aggressiveness coinciding with the administration of antibiotics of the family of the macrolides.