TEWKSBURY, Mass. – It’s Thursday morning at Tewksbury State Hospital, and patients are buzzing with excitement, already starting to line up.

Patients will sit and wait in the hallways, so as to catch a glimpse of one of their most cherished visitors, who has developed somewhat of a cult following at the hospital: Tucker, a little white cockapoo with floppy ears, has arrived to do pet therapy”

And he’s so small and adorable that people can’t help but stand up and take notice when he struts down the hospital corridors.

“They get really excited,” said Nancy Marshall, therapy recreation coordinator for the hospital. “They wait for the dogs. They know the day and time they come. And they wait nearby and say excitedly, ‘This is the day that Tucker is going to come down the hall.’ “

The pooch will go room-to-room visiting about 20 patients. And Tucker will sit on their laps, perform tricks for them and gaze adoringly into the eyes of patients who pet and nuzzle him. Other times, the dog will sit quietly with a patient, who will pat him.

At the unit where Tucker visits, the pooch is considered by patients as “their pet,” too. And some even post little photos of him close to their bedsides.

Marshall said she started the hospital’s pet-therapy program in June 2009, after reading studies that touted the positive benefits that pets have on patients. They lower patients’ blood pressure, even prodding patients to become more active — giving them something positive to look forward to every week.

“They tend to have a very settling and calming effect,” said Liz Cleaves, a trainer and owner of Auntie Dog, a dog-training and day-care business in Tewksbury.

She has volunteered her dogs for pet therapy since the hospital program started. Her dogs, a Doberman pinscher named Panzer de Grosseretterhund, a German shepherd dubbed Jaeger von Olympia, and a Boston terrier named Newman von Tude, volunteer on a rotating basis every Wednesday afternoon.

There’s simply something to be said about “that canine connection,” she said.

People who don’t want to walk or have mobility issues will walk the dog or ride in their wheelchairs right next to it. Or they’ll play catch, throwing a white plastic dumbbell back and forth, inviting the dogs to fetch.

And patients won’t even realize they are doing occupational therapy, exercising their arms and hands, she said. “They just think they are playing with the dog.”

Her decision to volunteer her dogs for pet therapy stems from a memory from the 1970s, when her grandmother was in a nursing home. “I went to visit her one day,” Cleaves recalled, “and she had a stuffed animal, and she said, ‘Oh, I wish this dog were real.’ “

That experience struck Cleaves, making her realize how saddened she’d be, as a dog lover, if she couldn’t interact with animals on a daily basis when she got older.

“I just hope someone will bring their dog to see me when I get older,” she said. “If you have grown up in a home with animals, you just can’t imagine how delightful it is to see this bundle of fur come through your door.”

Cleaves looked into pet-therapy training programs several years ago and found a workshop, which costs $35, run by the nonprofit Dog B.O.N.E.S. Therapy Dogs of Massachusetts, which trains dogs and their owners to serve as pet therapy teams and help to place them in volunteer positions. Annual membership to the organization is $25.

Since that time, she volunteered her dogs at Tewksbury Hospital and in the past months started volunteering her dogs with the elderly at an assisted-living facility, Emeritus of Tewksbury, formerly The Pines.

Beth Taylor, memory-care director for Emeritus at Tewksbury, has been using pet therapy for several months.

“Our residents are very responsive to the Big Three: music, babies and animals,” she said.

“I have found the elderly population has an inexplicable connection to animals,” she said. “Animals just make them feel good. It’s something for them to focus their attention on, and our residents love anything that needs to be nurtured.”