According to the search results, taking two birth control pills in one day is generally safe and wont have any serious long-term health effects. However, it may cause some short-term symptoms such as feeling slightly nauseous or experiencing vaginal bleeding. If you accidentally take an extra pill, you should continue taking the rest of your packet as normal at the same time you usually take it each day. If you experience severe symptoms or are concerned, you can talk to your pharmacist or GP, or contact NHS 111. Its important to continue taking your pills as usual, even if youve taken an extra one, to maintain the effectiveness of the contraception.