no. there is no evidence that cephalexin will affect birth control pills. it is a common belief that all antibiotics interfere with the efficacy of birth control pills though that is not always the case. missing a dose of your birth control pill or vomiting or diarrhea from your antibiotic may affect your hormone level. these reactions could affect the efficacy of your pills. talk to your pharmacist about any of your concerns regarding drug interactions. they can help.
will taking cephalexin interfere with birth control?