Alcohol and tobacco use (including smokeless tobacco, sometimes called “chewing tobacco” or “snuff”) are the two most important risk factors for head and neck cancers, especially cancers of the oral cavity, oropharynx, hypopharynx, and larynx (2–5). At least 75% of head and neck cancers are caused by tobacco and alcohol use (6). People who use both tobacco and alcohol are at greater risk of developing these cancers than people who use either tobacco or alcohol alone (6–8). Tobacco and alcohol use are not risk factors for salivary gland cancers.Infection with cancer-causing types of human papillomavirus (HPV), especially HPV type 16, is a risk factor for some types of head and neck cancers, particularly oropharyngeal cancers that involve the tonsils or the base of the tongue (9–11). In the United States, the incidence of oropharyngeal cancers caused by HPV infection is increasing, while the incidence of oropharyngeal cancers related to other causes is falling (9). More information is available at the HPV and Cancer page.Other risk factors for cancers of the head and neck include the following: