A group of California residents have filed a lawsuit against Starbucks and claim the popular coffeehouse chain discriminates against lactose-intolerant customers.

The $5 million class action lawsuit represents Maria Bolliger, Dawn Miller and Shunda Smith, three women who allege Starbucks has violated The Americans with Disabilities Act (ADA) by charging lactose intolerant coffee lovers like them more for nondairy milk options, according to the Los Angeles Times.

In expensive cities such as San Francisco and New York City, alternatives to cow milk such as oat, almond, coconut and soy milk can add up to 90 cents to a customer’s bill.

The lawsuit claims Starbucks is adding a surcharge to these products even though milk costs are comparable to lactose-free options.

This leads Bolliger, Miller and Smith to pay between 50 and 80 cents more on their orders to substitute 2% milk with an alternative.

When the lawsuit was filed, dairy products like whole milk, half & half and heavy cream were priced between 3 and 32 cents per fluid ounce.

In comparison, soy, coconut, almond, and oat milk often sell for between 4 and 7 cents per fluid ounce.

The lawsuit states, "Upon information and belief, Starbucks has earned over $1 billion dollars in the United States as a result of its discriminatory and illegal levying of the Surcharge during the class period."

The ADA defines lactose intolerance as a disability that can cause digestive tract inflammation, bowel irregularities, stomach pain, and vomiting. It affects between 30 and 50 million Americans. 

Keith Gibson, one of the attorneys representing the plaintiffs, said Starbucks is choosing to offer oat milk and almond milk but not offering the alternatives to customers freely.

"For these people, it’s not a choice since they can’t drink regular milk. Charging a surcharge is discrimination against them," he told The Los Angeles Times.

Gibson previously represented plaintiffs in a similar lawsuit against Starbucks in Florida. While he did not reveal whether a settlement had been reached, he said the new lawsuit filed in the U.S. District Court in Fresno, Calif., has nationwide implications.

U.S. Justice Department spokesman Adam Cyr told the outlet that the ADA requires businesses to make reasonable modifications to typical company policies to accommodate customers with disabilities.

A Starbucks spokesperson told The Los Angeles Times on background that customers are able to add up to 4 ounces of nondairy milk to hot or iced coffee and tea, cold brews, or Americano beverages for no additional charge. They also noted that Starbucks Rewards allows members to redeem points to substitute for nondairy options.

Starbucks told Fox News Digital it cannot comment on pending litigation.