If you come from a certain part of the United States—and happened to grow up in the 1970s and '80s—you know Mr. Yuk's day-glo green face. For 43 years, this sticker has served as a defense against poisoning, warning kids that what's in that package isn't safe to eat. In honor of National Poison Prevention Week, here's a look back at the history of the iconic symbol.

A Jolly Roger Problem

Mr. Yuk's story begins in Pittsburgh, Pennsylvania, in 1970. Dr. Richard W. Moriarty, then a chief pediatric resident at the Children's Hospital, noticed that there were many calls about poisons coming to the emergency room, not to mention many needless visits, when parents should have been calling Poison Centers first. "Frantic parents were making mad dashes to emergency rooms when what they needed to do was to call a poison center, get the right information and, more than likely, sit tight," Moriarty told the Western Pennsylvania History journal.

Complicating matters was the fact that the Jolly Roger—a skull and crossbones that had traditionally been used to warn kids of poisonous substances—had been incorporated into the logo of the Pittsburgh Pirates, and appeared on everything from cereal boxes to gum labels. “Children are relating the danger symbol for poison with pleasant surroundings,” Moriarty, then director of the Pittsburgh Poison Center, told the Pittsburgh Post-Gazette. The confusion may even have led to an uptick in poisonings in the area.

What Pittsburgh needed was a symbol that did two things: It had to be unpleasant enough to get kids to pay attention, and informative enough to get parents to call Poison Centers. Those centers would not only offer advice to parents, but also inform the appropriate hospital of important clinical information if the child did, in fact, need to go to the ER.

From the Mouths of Babes

Moriarty and a team of experts—including Pittsburgh PR agency Vic Maitlan and Associates rep Dick Garber—led the charge. They began by conducting discussions with kids 5 and younger about poisons. "We asked what might happen to you if you put something bad into your mouth that could make you sick," Garber told Western Pennsylvania History. "They said, 1) their mother would yell at them, 2) they would die, and 3) they’d get sick.”

An artist drew the three potential new symbols: Mad, comprised of an angry face on a stop sign; death, a face based on the skull and crossbones, in black and white; and sick, a variation on the smiley face with an expression that instead invoked an upset stomach. The symbols were presented to the kids, who were asked to rank them according to which faces they liked best. The sick face almost always finished last.

The team also polled kids on the color of the sticker. After testing eight different colors, the team found that children were particularly put off by that day-glo fluorescent green. In fact, one kid, when he saw the sticker in that color, made a sour face and said, "He looks yucky."

And just like that, Mr. Yuk had a name. "The skull and crossbones was designed by adults for adults," Moriarty told the Post-Gazette. "Mr. Yuk is actually the first symbol specifically designed for kids." And by kids, too: The final logo was created by fourth grader Wendy Brown from West Virginia as part of a contest sponsored by the Pittsburgh Poison Center. With the addition of the local poison center's phone number in the black band surrounding his face, Mr. Yuk was finished.

Rolling Out Mr. Yuk

In 1971, Garber and Vic Maitland and Associates created a 60-second Mr. Yuk commercial on a tight budget. The sticker even got its own theme song (sample lyrics: “Mr. Yuk is mean / Mr. Yuk is green”) penned by writer Barbara Bolton:

By 1973, more than two million Mr. Yuk stickers had been distributed, according to the Post-Gazette, and in 1975, the Mr. Yuk commercial above aired during the Super Bowl between the Pittsburgh Steelers and the Minnesota Vikings. By 1979, 50 million stickers were being distributed annually.

Though some studies have questioned the effectiveness of Mr. Yuk and other poison-awareness symbols, Edward P. Krenzelok, director of the Pittsburgh Poison Center, credits Mr. Yuk and the invention of child-proof caps with a sharp decline in cases of poisoning in Pittsburgh. "Up until the early 1970s, as many as three to five children in the Pittsburgh region were dying each year as a result of accidental poisonings," Krenzelok said in 2006. "Due in large part to poison prevention program Mr. Yuk has made famous and the development of child-resistant caps, there have been less than five accidental poisoning fatalities in Pittsburgh over the last 30 years."

There have been other popular poison symbols, from Officer Ugg to Uncle Barf, but none has been as enduring as Mr. Yuk; one federal study conducted in 2006 reported that three out of four Americans recognize the sticker. A variety of Yuk educational and promotional materials are still available today, and you can even get a free sheet by sending a self-addressed stamped envelope to:

Mr. Yuk

Pittsburgh Poison Center

200 Lothrop Street

PFG 01-01-01

Pittsburgh, PA 15213

For more on the history of Mr. Yuk, check out "Still Scary After All These Years: Mr. Yuk Nears 40" [PDF] from the Western Pennsylvania History journal.