Dienogest does not require that you start taking it the day after your period; you can start taking it any day after you begin treatment. Dinogestrel is a selective progesterone receptor agonist that inhibits ovarian function, reduces the pain that accompanies endometriosis, and causes lesions to shrink and atrophy. Dinogestrel can be started on any day of the menstrual cycle. Dinogestrel must be taken continuously, and irregular vaginal bleeding may occur during the course of the medication; if one box is completed, the next box is started. Dienogest is an oral preparation, one tablet daily without interruption, preferably at the same time each day, taken with water if needed, after a meal or on an empty stomach. Specific medication should be taken under the guidance of a doctor, not blindly on your own to avoid adverse effects.