Do antibiotics affect the morning after pill?

Most antibiotics don't affect contraception or emergency contraception (morning after pill). It's now thought that the only types of antibiotic that interact with hormonal contraception and make it less effective are rifampicin-like antibiotics.

These can be used to treat or prevent diseases, including tuberculosis and meningitis and include rifampicin and rifabutin.

Other antibiotics do not make hormonal birth control less effective.