Strong antibiotics such as Cipro, Avelox, and Levaquin have been known to save lives in patients suffering serious diseases, especially travelers who fall ill when visiting foreign countries—but these powerful drugs can also kill beneficial bacteria that protect the body, leading to caution on use in only extreme cases. “This makes room for new bacteria to colonize your gut. And antibiotics select for the ones that are resistant to the drug,” says infectious disease doctor Anu Kentele of Helsinki University Central Hospital. He led a study published January 2015 in the journal Clinical Infectious Diseases, finding that treating minor infections like the stomach bug with strong antibiotics such as Cipro, Avelox or Levaquin can increase the risk of catching drug-resistant microbes from developing countries. These resistant bacteria can live in the body for years, and are easily spread. Risks associated with antibiotic misuse, coupled with other known side effects of Cipro, Avelox or Levaquin including potentially-permanent peripheral neuropathy, might make travelers think twice before popping pills.