Oxford University has found that taking an aspirin a day can significantly reduce the risk of cancer and its spread throughout the body by about 40-50%. While the efforts of this study may seem groundbreaking, results have not been noticeable until 8 to 10 years after the start of treatment. In addition, there is an increased risk of internal bleeding. More research is currently being conducted, and it is advised that you talk to a doctor before starting any pill regiment.