There are different types of short-acting contraceptive pills, some in a 21-day course and others in a 28-day course, all taken once a day, preferably at night. Pills that are used for 21 days a month include drospirenone ethinyl estradiol tablets and deoxyprogesterone ethinyl estradiol tablets, which are usually started on day 1 of the menstrual cycle, taken on an empty stomach two hours before bedtime for 21 days, then stopped for seven days before the next box of pills is started. Drospirenone ethinyl estradiol tablets (II) and other medicines for a course of 28 days, usually also from the first day of menstruation that is to start taking once a day, once a day, every night at a fixed point in time to take a piece of oral, for 28 days. 28 days that is, after the box, and then take the second box of the first tablets can be, in the middle of the drug does not need to be discontinued. However, it should be clear that you are not pregnant before taking the medication. It should be noted that the drug may cause side effects, different drugs may be different dosage and duration of treatment, should be used under the guidance of a doctor, do not blindly use the drug. If any abnormality occurs after taking the medicine, consult a doctor promptly.