If you accidentally take two birth control pills in one day, it is safe and most likely wont have any long-term health effects. However, you may feel slightly nauseous that day, but the feeling will pass quickly. You should continue taking the rest of your pills as usual at the same time each day, and you dont need to seek medical advice unless your symptoms are severe. If you miss a pill, take it as soon as you remember, even if that means taking two pills in one day. Its important to continue taking the pill at the same time each day because some types of pills are only effective if taken every 24 hours. If youre worried about pregnancy prevention, you might consider using a backup method of protection, such as a condom, for at least a week after the slip.