Will the progestogen-only pill be effective if I vomit or have diarrhoea?
If you vomit within two hours of taking the progestogen-only pill or if you have very severe diarrhoea the pill will not have been absorbed by your body. If this happens continue taking the pill as usual and use an additional method of contraception, such as a condom, during the time you have a stomach upset and for two days after.