Typically, Labor Day marks the unofficial end of summer on our calendars, as we begin to put away the bathing suits, summer dresses, and sandals to make room for the fall. However, for coffee lovers, the end of summer begins when Starbucks releases its popular seasonal fall drink before its official launch date in September. While many of us wait in line day in and day out rejoicing at the return of the Pumpkin Spice Latte (PSL), or “fall in a cup,” do we know what’s in this addictive drink? Vani Hari, nutritionist blogger known as Food Babe, says the drink contains carcinogens, high-fructose corn syrup, a “toxic” dose of sugar, and surprisingly — no pumpkin.

Since its initial launch in 2003, there have been more than 200 million Pumpkin Spice Lattes sold, according to Starbucks’ website. Now the franchise is under attack by Hari, who wants Starbucks to remove carcinogen-causing ingredients like Class IV Caramel Color. The blogger has already tackled everyone from Kraft to Subway to Chick-fil-A. She broke the seal on what’s really in Starbucks' most popular fall drink in her blog post: “You'll Never Guess What's in a Starbucks Pumpkin Spice Latte (Hint: You Won't be Happy)."

"While [Starbucks lists] some ingredients on their website, they still do not list the ingredients in their most popular items: their drinks. This includes all of their lattes, Frappuccinos, Macchiatos, smoothies, etc. Starbucks doesn't even publish the ingredients in their kids drinks, keeping parents completely in the dark," Hari wrote on her blog.

In a back and forth email exchange with Lisa Passe, Starbucks spokeswoman, and looking into the franchise’s online store, Hari was able to get the overall list on ingredients in the PSL. Although Starbucks prides itself in its transparency, Hari and customers alike wonder why the company doesn't just publish its list of ingredients online. In response, Passe says there are more than 170,000 ways to customize Starbucks beverages, so listing ingredients in every case can be very complex, but she remarks, "We're working on listing core beverage recipes online via Starbucks.com and hope to have an update in the near future."

To save customers’ time and money, Hari lists the harmful ingredients in PSL we should all be on the lookout for:

Class IV Caramel Coloring

This coloring agent has been linked to causing cancer in numerous studies, making it a carcinogen. A 2007 study published in the National Toxicology Program Technical Report Series found that feeding mice caramel coloring IV — which contained 4-Mel — increases their risk of developing lung cancer and leukemia at every dosage level. Consumers will get two doses of Class IV Caramel Coloring in their PSL, and even Starbucks' whipped cream contains the carcinogen.

Linda Mills, a Starbucks spokeswoman who spoke with Business Insider, mentioned the company is planning to eventually remove caramel coloring from the drinks. "We are actively looking at phasing out caramel coloring," she said. "In any instances where it is used in our beverages, the level is well below the No Significant Risk Level (NSRL) and safe to consume." Now, while the level is below what’s allowed, what if a consumer has a Venti with the double dose of caramel coloring within the syrup and whipcream? The “safe” level of 4-Mel should be 29 micrograms/day, according to California’s Prop 65.

Monsanto Milk

Starbucks has yet to serve organic milk, but they have stopped using milk from cows injected with growth hormones. However, Hari notes their milk still comes from cows that are fed genetically modified (GMO) feed all day long. Cows commonly eat corn, soy, alfalfa, cotton side, and sugar beets. The issue derives from the fact 60 to 90 percent of world soybean exports come from GM plants, and more than half of the worldwide production of soybeans is GM, according to Liberty Voice. When cows are fed this cheap grain diet, this contributes to the overuse of antibiotics and the spread of antibiotic-resistant bacteria.

Consumers can opt for Starbucks Organic Soy Milk plain or vanilla, but vegans should be warned this isn’t a non-vegan product. The Pumpkin Sauce in this drink contains condensed nonfat milk, which leads to more misinformed customers. A soy latte will not do you any better, as the franchise’s “proprietary” organic soy milk contains carrageenan — linked to gastrointestinal inflammation and cancer. This ingredient adds a dose of added sugar, preservatives, and natural flavors, according to Hari.

High Fructose Corn Syrup

There have been conflicting answers from Starbucks about whether or not the lattes have any high fructose corn syrup (HFCS). Hari received an email from Passe that says the standard pumpkin lattes sold in stores do not contain HFCS and are sweetened with sugar. However, the Fontana Pumpkin Sauce, which is available on SatrbucksStore.com — for customers who want to make it at home — contains HFCS.

For a complete list of ingredients in a PLS, Hari has posted a chart that dissects America’s favorite fall drink.