Food delivery service, Deliveroo, is overhauling its menus to display more allergen information starting in December.
Ingredients such as sesame seeds, nuts or dairy will be flagged up on every dish that contains them.
Tortilla and Chipotle will be among the first chains to adopt the new system.
The move follows the deaths of two Pret a Manger customers who suffered allergic reactions to food they bought at the sandwich chain.
At the moment Deliveroo's app does not display detailed lists of ingredients, instead customers have to get the information direct from the restaurants.
Customers can alert Deliveroo to the allergies they have, but in the past some have complained on social media that the system hasn't worked.
Ordered a burrito for lunch. Picked vegetarian (no guac). Put in an allergy note : allergic to avocado.— Spoookolas 👻☠ (@NioclasN) October 2, 2018
Arrives with guacamole
Thank you @boojum_dublin and @Deliveroo_IE for trying to kill me pic.twitter.com/N0vhb3S6w5
wish more restaurants would add allergy information on @Deliveroo, it’s no help to me saying something has “special sauce” when i don’t know what’s in the sauce 😭😭😭— Beth✨ (@BethCharlotteP) October 4, 2018
After a test phase in December, Yo! Sushi, PizzaExpress, Pho and Byron will join Deliveroo's new menu display in January, before it is rolled out to the rest of Deliveroo's partners during 2019.
"Overhauling our menus is not a simple task, but customers with allergies need this extra transparency before they order," said Dan Warne, managing director for Deliveroo UK and Ireland.
The new version of the app will also make it easier for customers to communicate directly with restaurants, the firm said.
Before the roll-out of the new service is complete, Deliveroo said it was making immediate changes to make existing allergen warnings more prominent.