How do I show allergens and warn customers about them?

Map the product metafield that holds each meal's allergens. Customers who name an allergy in guided start then see a warning on the meals that contain it, and you choose separately whether every card lists its allergens.

Steps

1. In Shopify, store each meal's allergens in a product metafield (Settings → Custom data → Metafields → Products). Plain text like “Milk, Soy, Wheat” works, and so does a list field. Fill it in on every meal.
2. In the app, open Menus, then the Settings tab, and find Allergens on menu cards.
3. Choose your Allergens metafield and click Save.
4. Click “Apply to products already in menus” so meals already on a menu pick up their allergens.
5. Optional: turn on “List allergens on every menu card” if you want every card to show its full list. Leave it off and a card shows an allergen line only when that customer is avoiding something in the meal.
6. Check that your Guided start allergy options match the words you use on your products: Menus → Guided start, open the allergens step, and make sure each option's Exclude tags list the words your metafield uses (for example the “Gluten” option should list “gluten, wheat” if your products say Wheat).

Frequently asked questions

How does a customer see the warning?

On the meals that contain an allergen they selected, the card shows “⚠ Contains milk” under the title and the photo is dimmed. The meal can still be chosen — the warning informs, it does not block.

A meal's allergens aren't matching what the customer chose

The words have to line up. Your product says Wheat, the customer clicked Gluten — the link between them is the option's Exclude tags in Menus → Guided start. Add every word your products use to the matching option, then reload the storefront menu; no re-import is needed.

Do meals without allergens show anything?

No. A meal with an empty metafield shows no allergen line at all. The app never states that a meal is free of an allergen — an empty field and a genuinely allergen-free meal look identical in the data, so only “contains” is ever shown.

I edited a metafield in Shopify and the card is unchanged

Allergens are read when a product is added to a menu, like nutrition. Click “Apply to products already in menus” in Menus → Settings to refresh every menu at once, or re-add the individual product.