The human papillomaviruses (HPV) are small viruses with double stranded DNA that have a particular tropism for the epithelium inducing its proliferation. It is believed that the HPV enters the body after slight trauma to the epithelium and needs terminally differentiated epithelial cells for replication. Human papillomaviruses cause epithelial lesions of varying severity. Over 100 different human papillomavirus types have been identified and each is associated with a different type of lesion. HPV type 1 causes verrucas, HPV type 2 causes common warts and HPV type 11 causes genital warts. Certain HPV types, such as HPV16 and HPV18 infect cervical epithelium and cause lesions that can progress through different grades of cervical intraepithelial neoplasia to cancer. These viruses are known as ‘high-risk’ papillomaviruses. Most ‘high-risk’ HPV infections are successfully resolved by the host immune system and do not become life-threatening. In a small number of cases however, lesions caused by ‘high-risk’ HPV types can persist and can develop into cancer.