Taking the pill for the first time may produce gastrointestinal symptoms, withdrawal bleeding, contraceptive failure and so on. 1. Gastrointestinal symptoms: nausea and vomiting, loss of appetite, fatigue and other symptoms may occur, these are the adverse effects of taking the pill, usually the symptoms are relatively mild, will disappear naturally within twenty-four hours, without special treatment. 2. Withdrawal bleeding: after taking birth control pills, there may be vaginal bleeding after stopping, which is called withdrawal bleeding. 3. Contraceptive failure: If the emergency contraceptive pill is taken after seventy-two hours after sexual intercourse, if it is not taken according to the time, it may lead to the possibility of pregnancy and cause contraceptive failure. If there is any abnormality after taking the pill for the first time, you need to go to the hospital in time, and be treated by the doctor according to the specific situation and make individualized diagnosis and treatment plan.