In 1992, New York vigilante Curtis Sliwa was shot multiple times in an assumed mob hit, thought to be the work of the notorious Gambino family’s John Gotti. Miraculously, he survived — but 20 years later, his wounds came back to haunt him.

Sliwa, the famous red beret-donning founder of the Guardian Angels, was left with five hollow-point bullet wounds and internal damage from the attack. He underwent multiple surgeries, and needed a colostomy bag for two years. “The surgeons warned me that if the hollow-point bullets didn’t kill me . . . they would cause me more gastronomical issues [down the line],” he tells The Post. “And they did”: He ultimately developed severely ulcerated intestines.

“It’s like having Dante’s ‘Inferno’ in your stomach,” says Sliwa from his hospital bed at Columbia’s NewYork-Presbyterian. Until two years ago, he weighed a muscular 210 pounds. Then, the severe stomach pain struck. His muscles withered away. He dropped 60 pounds because he couldn’t keep himself fed. About a month ago, he was officially diagnosed with Crohn’s, a notoriously unpleasant inflammatory bowel disease.

Sliwa’s stomach is so torn up that even the simplest meals can put him in agony. For the past six months, his diet has consisted of turkey sandwiches and Gatorade exclusively. “Anything else, [and my] whole stomach would become a granite block,” he says. “There’s reflux, and I’m nauseous all the time.” Some days, he gets sick for hours on end.

His stomach specialists at New York University tried everything, including an unpleasant-sounding drug that Sliwa describes as “a form of medical Drano.” Finally, as a last-ditch effort, Sliwa underwent a grueling 6 ¹/₂-hour surgery last week with Dr. Ravi Kiran, chief of colorectal surgery at NewYork-Presbyterian/Columbia University Medical Center. The goal: to “rejoin” parts of his torn-up intestines.

This surgery is considered the end of the line for Crohn’s disease, Kiran tells The Post, and it’s rare. “[This] level of complexity, we see in very few patients . . . possibly 1 to 2 percent.” Sliwa’s case was among the most urgent he’s seen: He had “oceans” of Crohn’s in his body, and “the longer you put off surgery . . . it can become more difficult, because the disease gets worse and worse.”

Five days post-surgery, Sliwa isn’t out of the woods yet. He’s being fed through a long IV and has received two blood transfusions. “The pain after the operation was worse than the pain I suffered from the gunshot wounds,” he says. He’s desperate to return to doing what he does best: riding the rails and fighting crime. “You have to suck it up because you have to be a role model to others,” says Sliwa, who adds that he had to cut back on patrols during the past two years.

Next on his agenda? Hopefully eating regularly again — “the goal is that he won’t live on turkey sandwiches,” Kiran says — and of course, resuming wearing his signature headgear. “The signal that I am feeling better will be when you see me wearing my red beret, but that’s still some time off in the future,” Sliwa says.