Taking a double dose of Cerazette should not affect her contraceptive effect, but the risk of side effects may increase. According to the Cerazette documentation: "No serious harmful effects have been observed after taking more than one tablet of Cerazette at the same time. Nausea, vomiting and slight vaginal bleeding may occur in both women and young girls. Seek medical advice." Please note, however, that this applies to an incidental double dose and the leaflet recommends that you contact your doctor: https://www.gdziepolek.pl/telekonsultacja Cerazette tablets should be taken at the same time each day - one tablet should be swallowed whole with water. The absorption of the medicine may be reduced if vomiting or severe diarrhoea occurs within 3 to 4 hours after taking a tablet of Cerazette. In case of severe diarrhea, you should contact your doctor. If you had doubts four times, such a consultation is probably advisable. I enclose additional information about the drug Cerazette - prescription drugs can be reserved at GdziePoLek and collected stationary upon presentation of a prescription: https://www.gdziepolek.pl/produkty/16697/cerazette-tabletki-powlekane/apteki/w-warszawie Perhaps our studies will be helpful: https://www.gdziepolek.pl/artykuly/jak-prawidlowo-stosowac-antykoncepcje