Antibiotics decrease the efficacy of hormonal contraceptives.

This isn’t true for MOST antibiotics.

You’ll still see interaction alerts for oral contraceptives plus penicillins or tetracyclines...but the data supporting an interaction are poor.

You’ve probably heard the theory that antibiotics lower estrogen levels by killing gut bacteria and interfering with the enterohepatic circulation of estrogen. The trouble is evidence doesn’t support this mechanism...or the presence of drug interactions.