Shortly after he was hired as the executive director of the California Milk Processor Board, Jeff Manning had an epiphany. It was 1993. Sales of milk were sagging both in California and nationwide. Milk industry advocates had spent much of the 1980s promising that “Milk Does a Body Good,” with an ad campaign focused on its calcium and protein benefits. Consumers knew milk was good for them. But Manning realized they just didn’t care.

Instead, the ad agency Manning hired to revamp milk’s reputation focused on the complete opposite. Rather than dwell on everything milk could do for them, they decided that television spots should highlight the consequences of going without milk. Maybe it meant having trouble chewing a dry peanut butter sandwich or cookie. Or not being able to enjoy a bowl of cereal. During a brainstorming session, ad partner Jeff Goodby of Goodby Silverstein & Partners jotted down a tagline: “got milk.” Then he added a question mark. And for the next two decades, the Got Milk campaign, and its slogan, became as ubiquitous as Nike’s declaration that athletes “Just Do It.”

As recognizable as the ads were, sales figures told a slightly different story. While more people may have been thinking about milk than ever before, that didn’t necessarily mean they were drinking it.

As a result of public education and private health care, milk was a staple of kitchens everywhere in the 1950s and 1960s. Early 20th-century studies of questionable veracity fed milk to rats and marveled at their shiny fur. (Rats that got vegetable oil were scrawny.) Children lined up in front of steel milk containers at schools to get their daily serving; pregnant women were told copious amounts would be good for their baby. For many people, mornings were marked by the sound of clinking bottles of milk left on doorsteps, as common as mail delivery.

In the 1970s, a shift began. Milk, while still considered a fundamental part of diets, was seeing increased competition from soft drinks. Aggressive marketing campaigns from companies like Coca-Cola and Pepsi positioned soda as fun to consume, offering caffeinated energy and enticing packaging that sometimes promised prizes. Milk, in contrast, was plodding along in plastic or cardboard containers. If there was any carton design at all, it was typically a simple illustration of a cow. Drinking it became almost perfunctory.

By the 1990s, milk was under siege by soft drinks, sports drinks, and Snapple, which cloaked some of its sugary offerings in an all-natural aesthetic. Milk was on the ropes: Continuing to insist it was a healthier option was no longer effective, nor was it enough.

Research by Goodby Silverstein & Partners revealed an alternative. When discussing milk consumption, consumers kept returning to the idea that running out was a source of frustration. While they may not have longed for milk as a rule, the times they could have used it—in coffee, for cookies, for cereal—and didn’t have it gave them a fresh appreciation for the beverage. When the agency put a hidden camera in their own offices to capture their staff’s reaction to running out of milk, they noted it was one of disappointment. (And sometimes expletives.)

With Manning’s consent, the ad agency decided to focus on a “Milk and …” campaign, highlighting all the ways milk and food go together. That was ground down further, with Goodby and his partners making an open-ended question of a milk-deprived scenario. “Got Milk?” would present a worst-case scenario, letting consumers ruminate on the consequences of finding an empty carton. The ads would be funded California’s major milk processors, with three cents from each gallon of milk sold going toward the campaign—which amounted to approximately $23 million annually.

The first televised spot for “Got Milk?” is probably still the best-known. It features a radio listener eating a sticky peanut butter and jelly sandwich while following along with an on-air trivia contest. When the host wants to know who shot Alexander Hamilton, the man knows it’s Aaron Burr. But without milk to wash down his food, it comes out as “Anon Blurrg.”

The spot, which was directed by future Transformers filmmaker Michael Bay, was an immediate sensation when it premiered in October 1993. More than 70 spots followed, many presenting a similar doomsday scenario. In a Twilight Zone premise, a man arrives in what he believes to be heaven only to find he has an endless supply of cookies but only empty cartons of milk. In another spot, a newly-married woman expresses disappointment in her choice of a spouse. He thinks it’s because he bought her a fake diamond; she’s upset because he emptied a carton. Time after time, a lack of milk proves uncomfortable at best or life-altering at worst.

If the milk industry had stuck with “Got Milk?” and nothing else, it probably would have remained a cultural touchstone. But in 1995, the campaign got an additional boost when the Milk Processor Education Program, or MilkPEP, another pro-milk lobbying group, licensed the slogan to use with their own growing milk mustache print ad campaign spearheaded by the Bozell Worldwide ad agency. Celebrities like Harrison Ford, Kermit the Frog, and dozens of others appeared with a strip of milk across their upper lip. Manning also agreed to license the tagline to third parties like Nabisco—which printed it on their Oreos—and Mattel, which issued a milk-mustached Barbie. Cookie Monster endorsed the campaign. At one point, 90 percent of consumers in California were familiar with the “Got Milk?” effort, an astounding level of awareness.

Being amused by the spots was one thing. But was anyone actually drinking more milk because of them?

Milk lobbyists in California pointed out that the ads arrested the decline of milk consumption that had plagued the industry for decades. In 1994, for example, 755 million gallons were sold in the state, up from 740 million gallons in 1993. Manning also cited figures that indicated “Got Milk?” helped halt a slide that could have cost the industry $255 million annually in California alone—a drop-off that was stopped by that $23 million in ad spending.

But overall, it was tough for milk to regain some of the lost loyalty it had enjoyed in the 1950s. Between 1970 and 2011, average consumption went from 0.96 cups daily to 0.59 cups. With so many beverage options, consumers were often pushing the milk carton aside and reaching for Gatorade or soda instead. Changes in food habits didn’t help, either. Fewer people were eating cereal for breakfast, instead looking for yogurt or other low-calorie options.

“Got Milk?” was informally retired in 2014, replaced by a “Milk Life” campaign that once again brought nutrition back to the forefront.

Today, the average American drinks roughly 18 gallons of milk per year. (Unless, of course, they’re lactose-intolerant.) In 1970, it was 30 gallons. But there is hope: Plant-based milk made from almonds and other less-conventional sources are growing in the marketplace. “Got Coconut Milk?” may not be as catchy, but it might soon be more relevant than the alternative.