Lots of people love dogs madly and can't imagine their lives without them. Dogs are known to be loyal not just because you support them with food and shelter, but you can see their reaction after arriving from work or traveling for weeks or months and you will be sure that it is not about food and shelter. Another thing about dogs which is not common in many countries that they could be also trained for therapy and this is based on several studies to prove that they have a great role in stress and pain relief especially for children and elder people. As mentioned therapy dogs or animals, in general, have an important role in providing comfort and affection to patients in hospitals, nursing homes, schools and other situations that support their needs. Therapy animals are classified into: 1- Facility Therapy Animals: These animals are important for nursing homes for patients suffering from Alzheimer's, dementia or any mental disease. 2- Therapeutic Visitation Animals: These are household pets that are trained for visiting hospitals, rehabilitation facilities, nursing homes to provide comfort and joy to patients that are living away from home due to mental or physical illness. 3- Animal Assisted Therapy Animals: These animals work with occupational and physical therapists in therapy to assist individuals in meeting their recovery goals. Animals being certified for therapy should be also clean to protect the patients from any pathogens transmission during their visits, so they have to be bathed with antiseptic chlorohexidine shampoo before 24 hours before the visit and wiped with disinfectant wipes throughout their hospitals' visits. Therapy Dogs in hospitals proved that they elevate patients' mood and don't feel alone or boring anymore from their long stay especially for those who are in the Intensive care unit or cancer patients. Dr. Megan Hosey a psychologist wrote an article after she received the feedback of the patients from the dogs' visits at Johns Hopkins Hospital and showed that this leads to: 1- Improved mood. 2- Pain reduction. 3- Improved heart rate. 4- General better engagement with the medical care team. 5- Disconnect from sickness and feel secure and hopeful. Service Dogs also are amazing as they are trained to support a wide range of disabilities. They are allowed in all public and private facilities. The types of service dogs include: 1- Psychiatric Service Animals. 2- Seizure Response Dogs. 3- Autism Assistance Dogs. 4- Medical Alert Dogs. 5- Diabetic Alert Dogs. 6- Mobility Support Dogs. A study was published in 2010 by the Journal of the Society for Psychological Anthropology proved that children with autism socially benefit from interactions when service and therapy dogs were included. Another study was published in 2003 by the American Journal of Alzheimer's disease and other dementias showed a statistical significant decrease in agitated behavior and a significant increase in social interaction. Dogs don't act positively only for patients, they also have a great effect in prisons to reduce violence, cases of suicide, drug addiction and antisocial behaviors. They could also have a role to improve the relationship between inmates and guards.