A 15-year-old girl died after eating a Chips Ahoy cookie that she had mistakenly thought was free of nuts.

Alexi Ryann Stafford, of Weston, Florida, was at a friend's house when she saw an open package of the cookies.

The top flap of the red package was pulled back and Alexi mistook the cookies for Chips Ahoy's 'Chewy' version, which is also red.

But after finishing just one cookie, Alexi knew something was wrong. These 'Chewy' Chip's Ahoy cookies had been made with Reese's Peanut Butter Cups inside.

Alexi Ryann Stafford, 15, died after eating a Chips Ahoy cookie that she had mistakenly thought was free of nuts

Stafford, of Weston, Florida, was at a friend's house when she saw an open package of the cookies and mistook them for the brand's 'Chewy' version

The teen's mouth began tingling and she immediately went home, where her condition rapidly deteriorated.

'She went into Anaphylactic shock, stopped breathing and went unconscious,' her mother, Kellie Travers-Stafford, wrote in a post on Facebook.

'We administered two EpiPens while she was conscious and waited on paramedics for what felt like an eternity.'

Within 90 minutes of eating the cookie, Alexi was dead.

Travers-Stafford said the family's hearts were broken and that they are 'still in shock'.

'Our whole lives we dedicated to keeping our child safe from one ingredient, peanuts,' she wrote.

The top flap of the red package was pulled back and Alexi mistook the cookies for Chips Ahoy's 'Chewy' version, which is also red, and does not contain nuts

But the cookies were actually 'Chewy' Chip's Ahoy cookies with added Reese's Peanut Butter Cups. And after eating one cookie, Alexi realized her mistake

Alexi's mother Kellie Travers-Stafford wrote a heartbreaking post explaining her death

'As a mother who diligently taught her the ropes of what was okay to ingest and what was not, I feel lost and angry.'

'She knew her limits and was aware of familiar packaging, she knew what "safe" was.'

Travers-Stafford believes it wasn't enough for the Chips Ahoy box to have a 'small added indication' on the familiar red package to point out that there were peanuts.

'The company has different colored packaging to indicate chunky, chewy, or regular, but NO screaming warnings about such a fatal ingredient to many people. Especially children,' she wrote.

Travers-Stafford believes it wasn't enough for the Chips Ahoy box to have a 'small added indication' on the familiar red package to point out that there were peanuts

Now the devastated mother is hoping to share Alexi's story to make sure a similar tragedy doesn't happen to another family

'It's important to us to spread awareness so that this horrible mistake doesn't happen again.'

Travers-Stafford's post has been shared more than 500 times, and reached one writer who contacted Chips Ahoy and shared Alexi's story.

The company said in a statement that it takes allergies 'very seriously' and that all products are 'clearly labeled on the information panel of the packaging'.

'Across our Chips Ahoy! product portfolio, packaging color is indicative of product texture and is not indicative of the presence of allergens,' the statement read.

'We always encourage consumers to read the packaging labeling when purchasing and consuming any of our products for information about product ingredients, including presence of allergens.'