At first glance, the Skittles package appears to be just like the one sold in the candy aisle of a supermarket: It has block letters filled in with white, a flowing rainbow and a red candy that replaces the dot above the letter “i.”

A closer look reveals some small differences: a background pattern of small, stylized marijuana leaves; a warning label; and numbers that reveal the amount of THC, the intoxicating substance in cannabis, in each piece of candy.

The images are included in a lawsuit that the Wm. Wrigley Jr. Company, owned by the candy behemoth Mars Inc., filed in May against five companies for selling cannabis-infused edibles that look like our old friends Skittles, Starburst and Life Savers. Though the suit focuses on intellectual property rights, the plaintiffs also argue that the copycat products could lead people, particularly children, to mistakenly ingest drugs.

A spokeswoman for Mars Inc. wrote in an email that the company is “deeply disturbed” by the products.

America is at an interesting crossroads: one where Big Candy, vilified in the wellness era as a primary source of refined sugar, has become an unlikely sheriff in the Wild West of recreational marijuana consumption roamed by pandemic-stressed adults.

In recent years, lawsuits similar to the one filed by Wrigley have been brought by the Hershey Company (against TinctureBelle for products resembling Reese’s Peanut Butter Cups, Heath bars, Almond Joy bars and York peppermint patties), Mondelez International (against a company hawking Stoney Patch Kids) and Ferrara Candy Company (against a store selling Medicated Nerds Rope). These lawsuits have all been settled, with the smaller companies agreeing to halt production and sales of the offending products.

Many public health officials fret that without proper regulation, accidental ingestion cases will continue to rise among children as the availability of edibles grows. Some poison control centers have already observed this trend in their data.

For example, there were 122 cases of exposure to THC for children under 5 in Washington State in the first nine months of 2020, compared to 85 for the same time period in 2019. The most common side effects reported included vomiting, lethargy and chest pain.

While many edible companies operating in states where medical or recreational cannabis is legal strive to comply with their local regulations, the illegal market is still thriving.

“When companies like these create headlines for doing what we’ve purposely avoided at Wana, I feel anger and frustration,” said Joe Hodas, the chief marketing officer at Wana Brands, a Colorado company that sells cannabis-infused products.

A recent review of the websites belonging to defendants in the Wrigley suit turned up cannabis-infused offerings like Stoner Patch Dummies, the Worlds Dankest Gushers, Gasheads Xtremes Sourfuls, Trips Ahoy, Buttafingazzz and Caribo Happy Cola.

“The situation has become more and more egregious,” said Christopher Gindlesperger, a spokesman for the National Confectioners Association, a trade organization in D.C. with 350 members, including Mars Inc., Hershey’s, Ferrara and Mondelez. “The cannabis companies cannot and should not be allowed to tarnish existing brands at will. It creates consumer confusion.”

Discreet Little Treats

A majority of states now allow the use of medical marijuana (Alabama just joined the list), and 18 of them, including New York, have legalized recreational marijuana as well. Though sales in New York are not expected to begin until 2022 at the earliest, businesses are rushing to grab real estate and prepare for the market’s opening. Some are already selling Delta-8-THC, derived from hemp, in candy form.

The spread of legalization has brought more players and consumers into the edibles market. “Edibles are easy. They’re portable. You don’t have to find a space to step aside and smoke,” said Sean Arnold, a founder of Terradigm Consulting, which advises cannabis companies on licensing, infrastructure and product development.

Edibles have come a long way from the days of pot brownies, when half a pastry could lead to hours of debilitated function or to nothing at all. “Ten years ago it was the luck of the draw if you bought a brownie,” said Henry Wykowski, a lawyer who has focused on cannabis law for 17 years. “You didn’t know where you would wind up.”

Today, licensed manufacturers are required by states to test their products for potency and to label packages with the amount of THC in each dose, and in the entire package. Some edibles companies make products with small amounts of THC, allowing the inexperienced to experiment with dosages.

The accessibility of edibles and the discretion they afford has made them the fastest-growing category in cannabis, according to Surfside, a cannabis data-analytics company in New York. Surfside estimates that edibles have outpaced the growth of the rest of the cannabis market by 29 percent in the last three months compared with the same period in 2020.

Mr. Wykowski said that transgressions that may have escaped the notice of large corporations like Mars or Hershey’s in the past are on their radar today “because cannabis is big business now.”

He teaches a course on cannabis law at University of California’s Hastings College of the Law, and one of the sessions deals with laws around likenesses of other products. “Five or 10 years ago when cannabis was starting to take off, it was a joke to have something like Cap’n Punch, a cereal that’s infused,” Mr. Wykowski said. “But the industry has matured, and the people who know what they’re doing no longer engage in that kind of conduct.”

Nonetheless, he regularly works with edibles companies that receive cease-and-desist letters from candy corporations. Most of these cases do not reach the courts. “Ninety percent of the time people will look at the letter and stop,” Mr. Wykowski said.

Most legal cannabis companies strive to follow regulations closely.

Lightshade, which runs nine dispensaries in the Denver area, has an eight-person compliance and auditing team led by Charisse Harris. Ms. Harris said that there are four checkpoints at which a product is assessed, and that every week, her auditors do random checks in the stores.

Some red flags include products that feature any iteration of the word “candy” (for example, “kandy” or “candie”), and ones that do not come in packaging that meets state requirements around child safety, Ms. Harris said. “I say no a lot,” she added.

Compliance becomes more complicated for companies operating in different states, since there are no federal regulations around cannabis.

“In Florida, our packaging is black-and-white, and there are no images,” Mr. Hodas said of Wana, which operates in 11 states and in Canada. The gummies are a plain off-white color. In Colorado, on the other hand, the Wana container has a picture of pink watermelon slices and the gummies are a rich coral hue.

There are three main aspects of a candy that can be protected by trademark and copyright laws, said Nancy J. Mertzel, a lawyer who specializes in intellectual property law.

Take Hershey’s Kisses. “You have the name Kisses, which is a trademark, the shape of the candy itself, which is both a trademark and trade dress, and the packaging, which is protected by copyright,” Ms. Mertzel said.

Ms. Mertzel said other possible intellectual property protections include patents — for example, Mars has sought patents for its chocolate, which is more resistant to melting than other formulations — and trade-secret laws. The most famous example of a trade secret is the Coca-Cola formula; another is Hellmann’s mayonnaise.

The case Wrigley has brought against the cannabis copycats, Ms. Mertzel said, is straightforward. “I certainly understand Wrigley’s concerns about having its intellectual property used by a third party, and those concerns are exacerbated when it’s for a product that children really shouldn’t be getting,” Ms. Mertzel said.

She compared the public health concerns at stake to those that were widely discussed when the tobacco industry used cartoons to target children in the 1960s. Even the Flintstones were in on it, with Fred and Barney promoting Winston cigarettes in an infamous commercial spot.

Child-Proofing Cannabis

Andrew Brisbo, the executive director of the Marijuana Regulatory Agency in Michigan, said that preventing youth access to cannabis is one of the primary functions of the program he oversees. And edibles are top of mind.

“When we look at accidental consumption, edibles are a primary issue,” Mr. Brisbo said. “A young person won’t accidentally smoke a marijuana cigarette.”

Gillian Schauer, a public health and policy consultant who has worked with a number of states on cannabis policy issues, said there are two potential concerns with edibles from a public health policy perspective: overconsumption and accidental consumption.

Because edibles can take a while to kick in, people sometimes rush to eat more without waiting for the first effects. Some inexperienced users do not know what amount of THC they should consume and are not educated on the potential effects of cannabis. A low-dose amount is considered 1 to 2 milligrams of THC, but effects vary based on many factors, like body weight and how much food the consumer ate that day.

Accidental consumption can affect anyone, but, Dr. Schauer said, “it has primarily impacted children because they can confuse cannabis edible products with other edible products, because most edibles look like candy or cookies or cake.” She pointed to reports compiled by poison control centers in Colorado and Washington, the two earliest states to legalize recreational cannabis use, in 2012.

Between 2014 and 2018, annual calls to the Washington Poison Center about children under 5 being unintentionally exposed to cannabis nearly tripled, rising from 34 to 94. In 2017, Washington State began requiring that all edibles have a logo stating “Not for Kids” (not that this will mean much to a 2-year-old).

In Colorado, edibles are the leading method by which children under 5 accidentally consume cannabis. In 2019, in Colorado, 108 people under the age of 19 were accidentally exposed to cannabis. In 2011, the year before the state legalized recreational use, that number was 16.

Like Washington, Colorado now requires packaging of edibles to include a warning symbol. The state also bans the use of the word “candy” on any marijuana packaging, and the sale of edibles that look like people, animals or fruit.

Dr. Schauer said other ways to reduce the risks of accidental ingestion include mandating childproof packaging, requiring that each edible item in a package is individually wrapped, limiting the potency of each individual edible, and educating consumers who live with children on how to store their cannabis products.

Making packages that will not catch the eye of a child is important, she said. In Canada, for example, where cannabis is legal, federal law requires packaging to have a uniform color and a smooth texture, and not to have cutout windows, scents, sounds or inserts (among other requirements).

Despite the stringency of Canada’s laws, as recently as mid-May, a child was hospitalized in the province of New Brunswick after eating Stoneo cookies that were made to look like Oreos, according to the Canadian Broadcasting Corporation.

In America, state laws are far less strict; for the most part, they prohibit the inclusion of cartoon characters and make general statements about how the packaging should not appeal to a child.

“The risks can be much more limited than we’ve seen them be so far,” Dr. Schauer said.

Mr. Hodas has three children, aged 12, 17 and 19. He has been in the cannabis industry for more than seven years. When he has products at home, he keeps them secure in bags made by StashLogix. It may not slow down a motivated 15-year-old, but it will stop a toddler, he said.

“If you have it locked up, and you keep in a place where they can’t reach it or see it, that’s the best way to prevent ingestion,” Mr. Hodas said.

To parents of a certain age, the situation may bring to mind the 1983 public service announcement “We’re Not Candy,” in which a barbershop quartet of singing pills on television advises children “to have a healthy fear of us.”

That the products now under scrutiny are a form of candy, just enhanced — and that no one is watching the same screen anymore — makes it difficult to imagine a marijuana meme so memorable.