Pret a Manger has said that full ingredient labelling, including allergens, will appear on products after a teenager died from an allergic reaction to one of the chain's sandwiches.
Natasha Ednan-Laperouse, 15, from Fulham, south-west London, collapsed on board a flight in July 2016 after eating an artichoke, olive and tapenade baguette she had bought at a Pret outlet in Heathrow Airport.
The coroner at her inquest last week said she died of anaphylaxis after eating the Pret sandwich containing sesame, which she was allergic to.
Natasha's father Nadim said she died because of "inadequate food labelling laws", and joined the rest of her family in calling for a change in the law to save lives.
Pret has announced that full ingredient labelling will be introduced to all products that are freshly made in its shop kitchens, and labels will list all ingredients, including allergens.
The food company said it will start trialling full ingredient labelling on product packaging from next month, adding that this will be rolled out to all UK shops as quickly as possible.
Clive Schlee, Pret chief executive, said: "I want to say again how deeply sorry we are for the loss of Natasha.
"I said we would learn from this tragedy and ensure meaningful changes happen.
"I hope these measures set us on course to drive change in the industry so people with allergies are as protected and informed as possible.
"Nothing is more important to Pret right now."