A popular consumer advocate is going after one of Starbucks most popular seasonal drinks, the Pumpkin Spice Latte.

Vani Hari, who runs the blog Food Babe, claims the drink contains chemicals that could cause cancer, high-fructose corn syrup and a "toxic" dose of sugar.

She says Starbucks fails to list many of these ingredients on its website. Hari also notes that the Pumpkin Spice Latte contains no actual pumpkin.

A graphic containing her claims has been shared endlessly on social media this week.

"While [Starbucks lists] some ingredients on their website, they still do not list the ingredients in their most popular items: their drinks," she writes. "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."

In response to her blog, angry customers took to Starbucks' Facebook page to blast its alleged use of undisclosed ingredients.

But according to Starbucks spokeswoman Linda Mills, the drink does not contain high-fructose corn syrup, as Hari claims.

It doesn't contain any pumpkin, either, she acknowledged. The drink instead uses the core spices that flavor pumpkin pie, such as cinnamon, nutmeg and clove.

The Pumpkin Spice Latte does, however, contain caramel coloring, a chemical that food safety advocates claim has a potential cancer risk.

Mills says the company is planning to eventually remove that ingredient from the drinks.

"We are actively looking at phasing out caramel coloring," Mills wrote in an email to Business Insider. "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."

If customers have questions about any of the items offered in our Starbucks stores, Mills encourages them to ask their baristas for a list of ingredients.

"We’re also working on listing core beverage recipes online via Starbucks.com and hope to have an update in the near future," she said.