Is Firehouse Subs Spicy Mustard High in Histamine?

Firehouse Subs Spicy Mustard

High histamine

Spicy mustard is high in histamine, driven by the mustard itself and its vinegar base.

Food here is usually assembled to order from components that were prepped earlier in the day, so it tends to be fresher than a drive-through and less fresh than cooking at home. Histamine builds up as protein foods sit, so how long the chicken or beef has been in the warmer matters as much as what is in the bowl. Treat the rating above as a starting point.

A simple condiment of vinegar, mustard seed, salt, and spices.

Spicy mustard — the mustard is high, so this small squeeze carries more histamine than its size suggests.
Vinegar — the vinegar base is moderate and adds to the tang and the concern.

If you want a sauce, a plainer low-histamine dressing or none at all keeps your sub easier.

This rating comes from Firehouse Subs' own published ingredient statement, read on August 11, 2026. Restaurant recipes vary by location and change over time, so always check the current listing: source 1, source 2. How we rate foods →

Firehouse Subs Spicy Mustard and Firehouse Subs are trademarks of their respective owners. This page is an independent histamine reference and is not affiliated with, endorsed by, or sponsored by the brand.