A service dog is a type of assistance dog specifically trained to help people who have disabilities, such as visual impairment, hearing impairments, mental illnesses (such as posttraumatic stress disorder (PTSD)), seizure disorder, mobility impairment, and diabetes.
Desirable character traits in service animals typically include good temperament or psychological make-up (including biddability and trainability) and good health (including physical structure and stamina). Some service dogs are bred and trained by service dog organizations. Labrador Retrievers, German Shepherds, and Golden Retrievers are the most common breeds used as service dogs, but any breed or mix of breeds is capable of being a service dog, though few dogs have all of the health and temperament qualities needed. Such a dog may be called a "service dog" or an "assistance dog," depending largely on country. "Seeing eye dog" is frequently used as a genericized term, but it properly refers to dogs trained by a specific organization and not to all guide dogs.
In the United States, the applicable law covering places of public accommodation is Title III of the Americans with Disabilities Act of 1990.
On September 15, 2010, the United States Department of Justice, Civil Rights Division, Disability Rights Section, issued "ADA 2010 Revised Requirements; Service Animals." It states that:
"Service animals are defined as dogs that are individually trained to do work or perform tasks for people with disabilities. Examples of such work or tasks include guiding people who are blind, alerting people who are deaf, pulling a wheelchair, alerting and protecting a person who is having a seizure, reminding a person with mental illness to take prescribed medications, calming a person with Post Traumatic Stress Disorder (PTSD) during an anxiety attack, or performing other duties. Service animals are working animals, not pets. The work or task a dog has been trained to provide must be directly related to the person's disability. Dogs whose sole function is to provide comfort or emotional support do not qualify as service animals under the ADA."