The Internet is a valuable source of health information on topics such as diseases, conditions, therapies, medical products, and health and medical organizations. When used properly, it allows quick and easy access to such information from on-line medical libraries, universities, health associations and government agencies. However, the quality of health and medical product information on the Internet varies, and it is often difficult for the Internet user to identify the true source of the information and to determine whether it is reliable, complete and up to date.