There’s a photo of Charlie Amico in the hospital. He’s wearing the typical hospital gown, surrounded by the typical hospital machines. What doesn’t fit the typical picture is the giant German shepherd sitting attentively on Amico’s typical hospital bed.

The shepherd is called Harry and, in the year-and-a-half he and Amico have been together, the two have been literally inseparable.

“In that period of time we have only been apart for maybe an hour and a half,” Amico said. “That was because of surgery. He couldn’t come into the OR of course.”

Charlie, now 65 years old, is a veteran of the Korean War. He joined the U.S. Army in 1971, served on the D.M.Z. in 1973 and retired from the service in 1985, a sergeant, first class.

He may have left the service long ago — he later had a long career with the U.S. Department of Agriculture — but there have been lasting effects.

“I do have nightmares,” he said. “I have for many, many, many years. They go back all the way to the early ‘70s.”

And that is where Harry the dog comes in: “Harry wakes me up. He doesn’t wake me up hard - he wakes me up very gently. He takes his head and puts his head under my arm and breathes on my hand until I wake up.”

Harry is a medical service dog, and was trained and provided to Amico free of charge by an organization called Guardian Angels.

The organization is based in Florida, but Dr. Richard McFarland, a longtime Norwalk-based veterinarian, is the regional coordinator. This year, the Guardian Angels’ 3rd annual “Barks, Brews and BBQ” will be held at the Westport VFW, Sunday, Aug. 25.

What makes Harry special is his sense of smell. Actually, all dogs have a great sense of smell, McFarland said: “The dog’s ability to smell is at least 100,000 times greater than yours and mine.”

Harry — and other trained medical service dogs like him — put that sense of smell to use in tangible ways.

Amico, for example, is a diabetic and Harry warns him when his blood sugar count gets too high. He said the dog is “100 percent accurate.”

“It’s mind-boggling the capabilities that these dogs possess, how they are able to detect medical issues,” Amico said. “Harry is able to alert me that something is wrong. He can’t tell me directly what’s wrong — he’s not quite that capable.”

It started the very day Harry met Amico, when he travelled down to Florida where the dog was trained.

Amico suffers from frequent kidney stones and, at that initial meeting, Harry started trying to communicate that something was amiss.

“Probably two-and-a-half hours later I got a pain in my stomach,” he said. “I went into the restroom and I was bleeding.”

The results, according to McFarland, are clear. When a veteran returns from a war theater, They are not the same person,” he said, and that affects relationships, as well. “The person that you married is not that person anymore.”

Put a medical service dog into the mix and suicide rates drop precipitously. “It takes the divorce rate from 90 down to zero,” McFarland said.

When it comes to emotional support, the dogs’ can actually smell anxiety.

“When you get into an anxious state of mind, you get an adrenaline dump. It’s an instinctive save-yourself kind of reaction,” McFarland said. “The dogs can smell when there is an adrenaline dump.”

The dogs are then trained to interrupt your thinking, to stop the anxiety train from gaining speed.

“They jump up on the owner’s lap and say, ‘hey stop thinking about yourself. Start thinking about me,’” McFarland said. “Once it reaches a crescendo there’s nothing you can do. They are trained to mess with you. Jump up, bark at you. That gets you out of your head so you start focusing on the dog.”

But beyond that — beyond medical and emotional intervention — McFarland explained that the dogs take on the role of a combat buddy, for a veteran who is no longer in combat.

He said military personnel learn “The philosophy of ‘I got your back.’”

“That means you have to have somebody else’s back,” he said. “Well the dog has your back in that military sense. Constantly there, constantly faithful, will always be there.”