Antibiotics are medicines to prevent and treat infections. While the likelihood of infection after surgery can be reduced by giving patients preventative antibiotics, taking these antibiotics for more than 24 hours after routine surgery is usually not necessary and can increase the risk of side effects such as stomach aches, serious types of diarrhea, and antibiotic resistance (when antibiotics are used too much, they will not work anymore.) There are exceptions for example, where the surgical site has been contaminated (making the surgery not routine).Talk to your doctor if you have questions about how long you should take antibiotics after surgery.