 -- Every March, millions of Americans don green garb, eat green food and drink green beer, all to celebrate a heritage that may not be theirs.

On St. Patrick's Day, emergency room staffers prepare themselves for an uptick in patients, likely with several of them injured themselves in some sort of hilarious calamity. It differs from holidays such as Christmas or New Year's, when patients in need of emergency care often wait a day or two before seeking it, preferring to wait for a more "convenient" time, said Dr. Michael Lynch, a toxicologist and an emergency physician at the University of Pittsburgh Medical Center.

The holiday is on a Friday this year, allowing millions to perhaps take their celebration of Irish heritage to the next — and possibly painful — level.

"It's not a fun day to work because of the number of alcohol-related injuries," said Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital in Manhattan.

"A lot of these people are law-abiding people, professionals who just got carried away," said Dr. Rahul Sharma, the emergency physician in chief at New York–Presbyterian/Weill Cornell Medical Center. "Many times, it's embarrassing for them."

Beware of green food coloring

One St. Patrick's Day, Glatter witnessed a group of advertising executives panicking after they had lunch outside the office, he said.

During the meal, they decided to take part in the day's festivities by drinking green beer. The food coloring altered the appearance of not only the beer but the executives' teeth as well — just before an important meeting.

"Four or five of them came to the ER," Glatter said. "They were freaking out because they had to see the client."

The food coloring stained the plaque buildup on their teeth, he said, and getting rid of it was no easy task.

"It takes time," Glatter said. "It doesn't go away immediately."

Even with whitening strips, mouthwash, toothbrush and toothpaste, it can still take up to a week for the coloring to disappear and teeth to return to their normal shade, he said.

"People do stupid things on St. Patrick's Day," Glatter said. "And certainly the novelty of different foods is something that is interesting."

It may not be wise to paint your car green

In Indiana one middle-aged man sought emergency care after attempting to paint his dark-colored Honda Accord, said Dr. Timothy Pohlman, the senior trauma surgeon at Indiana University Health Methodist Hospital.

The man used a slippery enamel paint, spilled much of it on his driveway and ended up slipping in it, causing him to bump his head and break a few bones.

When the man got to the hospital, he was covered in so much green paint that doctors could not assess where his injuries were, Pohlman said.

"I saw him, and he was basically a green man," Pohlman said, adding that after nurses cleaned off the patient, staffers determined he sustained a concussion and some broken bones.

Leprechaun costume gone wrong

Pohlman also treated a middle-aged man who inadvertently took an extra dose of his erectile dysfunction medicine on St. Patrick's Day.

The man then decided to don a tight leprechaun outfit, Pohlman said.

The man was suffering from a painful, hourslong erection that was constricted by his costume when he arrived at the hospital, Pohlman said. His appearance sent emergency room staffers into a tizzy.

"Everyone tries to be professional, but you can't help but smile or even kind of laugh and try to do your best for this guy," Pohlman said.

Because of the man's condition, the costume was putting so much pressure on his groin that he couldn't remove it, Pohlman said. Initially, the man did not want doctors to cut the outfit off, because he spent a fair amount of money on it.

"He had to make a choice between his costume and his member," Pohlman said. "Once it was put to him in that way ... he prioritized accordingly."

The emergency room can be a festive place on St. Patrick's Day

Despite the uptick in alcohol-related injuries on St. Patrick's Day, they are usually sustained in an innocent manner — such as tripping or losing balance — rather than in a bar brawl.

The jovial tone of St. Patrick's Day "calms the furies that drive people's violent nature," Pohlman said.

Doctors say they see less trauma from fights or altercations on St. Patrick's Day, and the patients tend to hobble into the emergency room much earlier than on other days, Pohlman said.

"Instead of all the trauma at night we normally see, it happens in the light of day," he said.

On St. Patrick's Day, the emergency room can resemble a sea of green as patients come in wearing their green clothing, hats and necklaces, Lynch said.

In addition to trauma, patients often come in suffering from hypothermia, he added. St. Patrick's Day revelers can spend long stretches outdoors in cool weather, often wearing less than conditions warrant, and alcohol consumption can reduce body temperature.

Lynch even treated one patient who, after consuming hallucinogenic drugs, pranced around the emergency room thinking he was a leprechaun and throwing fake gold at hospital staffers.

One emergency room staple no one looks forward to on St. Patrick's Day: green vomit.

"We have sort of a green patrol going around and mopping up green vomit," Lynch said. "Every year, we know we're going to get at least one or two green vomits."