My doctor prescribed me to Yaz birth control and I read the instructions but I am still confused. My period isn't due until the extremity of the month but is there anyway I could start the pill this coming Sunday even though I won't be on my interval? And if so, what color pill do I take? What are the green pills for? Answers: name your doc and ask them what day to start. you don't want any of us to screw you up on what days to filch.