10. Alcohol
Many people enjoy a drink now and then, and when done responsibly and reasonably, there is probably not much to worry about. Those who make alcohol a part of their everyday life or drink to excess often should be aware that alcohol can be linked to cancer. A total of 27 separate studies concluded that there is a link between drinking too much and cancer of the colon, rectum, liver, mouth, esophagus, and even breast cancer.