Stroking a pet can help patients cut their amount of painkillers in half, according to a new study.
he research found that patients who had undergone hip or knee replacement operations needed less painkillers if they used pet therapy.
It is well known that animal owners are generally healthier than non-pet owners because they can help reduce stress and encourage exercise.
In Britain a charity called Pets and Therapy has been taking animals into care homes, hospices, hospitals and children's wards to help patients recover and reduce stress levels since 1983.
A conference in America has heard that patients recovering from joint-replacement surgery needed 50 per cent less pain medication if they used pet therapy.
Julia Havey, from the Loyola University Health System (LUHS), Chicago, who led the research, said: "Evidence suggests animal-assisted therapy can have a positive effect on a patient's emotional and physical well being.
"These data further support these benefits and build the case for expanding the use of pet therapy in recovery."
Ms Havey and colleague Dr Frances Vlasses raise puppies to become assistance dogs through a program called Canine Companions for Independence.
Dr Vlasses said: "As nurses, we are committed to improving the quality of life for others.
"This service experience has provided us with a unique way to combine our love for animals with care for people with special needs."
The findings were presented at the 18th Annual Conference of the International Society of Anthrozoology and the First Human Animal Interaction Conference (HAI) in Kansas City.