The eight-year-old dog, Jake, visited the Le Bonheur Children's hospital in Tennessee, and met a six-year-old patient Alex Gosa as a part of the hospital's new Pet Therapy scheme.
The boy, who lost a toe in an accident recently, stroked the golden retriever as part of "doctor's orders".
When he was told the dog is two years older than him the boy replied: "I'm catching up with him."
The treatment, more commonly known as AAT -animal-assisted therapy- has been used to treat patients with mental and physical health problems since the late 18th century, the 'Daily Mail' reported.
The study published in the US Early Childhood Education Journal showed that children in particular benefit from AAT.
Staff at the hospital said pet therapy has resulted in a better outcome for patients.
It concluded that as a child perceives animals as non-judgemental it is easier for the child to build up a 'social and emotional support system' with them.
The programme has been going on for two weeks and it is the first time animals have been allowed in the intensive care unit.
Hospital spokesperson Sara Burnett said both patients and staff have benefited.
"We all stop and pet them. Grandparents do. Physicians do. Family members and siblings. I think there is something disarming about seeing a dog in a hospital. It makes you stop your 'busyness' - to take a minute and pet a dog," she said.
