A Vancouver woman is warning allergy sufferers to pay extra attention when eating products from chain stores.

Unjali Malhotra, who is allergic to eggs, suffered a severe reaction after eating a yogurt parfait at a Starbucks in Las Vegas.

"My lips were swelling and I immediately ran to the bathroom [and] threw up."

Malhotra admits she didn't look at the ingredients, which did list egg, but didn't think she had to because it looked just like every other yogurt parfait she's ever purchased from the coffee giant.

"Same label, same container. It looked exactly what you would go down the street and get in Vancouver."

As a physician and someone who sources her food carefully, Malhotra doesn't think it's unreasonable to expect uniformity from chains that promise consistency.

She says a Starbucks representative told her it's an issue they're working on.

In a statement to CBC News, the chain said food offerings do vary from store to store so customers are advised to read the labels each and every time.

"You just can't let your guard down," Malhotra said.