Any website should indicate clearly and often who is responsible for the site and its information. The American Animal Hospital Association's consumer website, for example, clearly notes its affiliation on every major page and includes a link to the AAHA home page. 

Health-related websites should provide information about the medical credentials of the people who prepare or review the material. Veterinarians in the United States are doctors of veterinary medicine (DVM) or veterinary medicine doctors (VMD) - the equivalent of a medical doctor (MD) in human medicine. Common specialist credentials include DACVIM (internal medicine), DACVS (surgery), and DACVD (dermatology).

It costs money to run a website. The source of funding should be clearly stated or readily apparent. For instance, web addresses ending in .gov are sponsored by the federal government; .edu indicates educational institutions; .org is often used by noncommercial groups; and .com denotes commercial enterprises. The source of funding can affect what content is present, how it's presented, and what the site owners want to accomplish.

Websites should be reviewed and updated regularly. It is particularly important that medical information be current and that the most recent update or review date be posted. Even if the information hasn't changed, it's helpful to know that the site owners have reviewed it recently to ensure that it's still valid. 

Many sites include an "About us" or "About this site" link, which should clearly state the purpose and help you to evaluate the trustworthiness of the information.

Reliable websites usually have a policy about how they link to other sites. Some medical sites take a conservative approach and don't link at all. Some link to any site that asks or pays for a link. Other link only to sites that have met certain criteria. 

Many health and medical websites post information collected from other websites or sources. If the person or organization in charge of the site did not write the material, the original source should be clearly identified. 

There should be a way for you to contact the site owners with problems, feedback, and questions. If the site hosts a chat room or other online discussion areas, it should tell you about the terms of using the service. Is the service moderated? If so, by whom and why? Before you participate, spend some time reading the discussion without joining in. 

In addition to identifying the original source of the material, the site should identify the evidence on which the material is based. Medical facts and figures should include references such as citations of articles in medical journals. Also, opinions or advice should be clearly set apart from evidence-based information (information based on research results).

Any e-mail messages should be carefully evaluated. Consider the origin of the message and its purpose. Some companies or organizations use e-mail to advertise products or attract people to their websites. The accuracy of health-related information may be influenced by the desire to promote a product or service. It's important to carefully consider the source of e-mail and other Internet-based information and to discuss the information with your veterinarian.