Yellow 5: what tartrazine is and what the rules say

Yellow 5 is tartrazine — FD&C Yellow No. 5 in the United States, E102 in Europe — a synthetic azo dye the FDA still lists for food in October 2026. US rules single it out twice: foods must name it, even butter and cheese, and drug labels must name it as tartrazine.

This page sets out what the dye is, the two US rules written for it alone, what the FDA’s 2025 plan does and does not change, how Europe labels it, and how it differs from Yellow 6. It reports what regulators have decided, not a verdict on what the dye does to anyone.

What is Yellow 5 made of?

Yellow 5 is principally the trisodium salt of a pyrazole carboxylic acid joined to a sulfonated benzene ring by an azo bond, CAS 1934-21-0. The US regulation describes the process: 4-amino- benzenesulfonic acid is diazotised and coupled with a pyrazole compound, and the dye is isolated as its sodium salt.

Every batch sold for food must be certified by the FDA before use, which is why the US calls it a certified colour. The same substance travels under several names, and a label can use any of the first five.

Two rules US law writes for Yellow 5 alone

Most certified colours follow one general labelling rule; Yellow 5 has two more of its own. Its regulation requires foods to name it, including butter, cheese and ice cream, and a separate drug-labelling section requires medicines to name it as tartrazine.

The butter, cheese and ice cream exception is the detail most label guides miss. For other colours, the general rule lets those three foods leave colourings undeclared; Yellow 5’s own regulation overrides that. The general rule also lets the FD&C prefix and No. be dropped, which is why packets print Yellow 5.

The prescription statement is written into the regulation word for word. It says the dye may cause allergic-type reactions, including bronchial asthma, in certain susceptible persons, and that sensitivity, though low overall, is frequently seen in people with aspirin hypersensitivity.

That statement is the US regulator’s own wording for prescription labelling, quoted here as a labelling requirement. It is not repeated on food packets, where the rule is the name alone.

Is Yellow 5 banned in the US?

Yellow 5 is not banned by federal law. On 22 April 2025 the FDA announced it would work with industry to eliminate Yellow 5 and five other synthetic dyes from the food supply by the end of the following year, and the regulation listing the dye for food remains in force.

The binding rules so far come from states, and both of the ones this page has read are narrower or less settled than headlines suggest. California’s law covers public schools; West Virginia’s broader law was challenged in federal court within months of passing.

This page does not track the West Virginia appeal or other states’ laws it has not read in full, so the table is a dated record rather than a complete map. The federal position is the stable reference: until 21 CFR 74.705 changes, Yellow 5 remains a listed colour for food.

Is Yellow 5 allowed in Europe?

Yellow 5 is authorised in the European Union as E102 tartrazine, in the group of colours that share a combined maximum limit. The EU attaches a labelling statement to it: a food containing E102 must say that the colour may have an adverse effect on activity and attention in children.

The statement is a labelling obligation set in the regulation, not a finding about any one product, and it applies to six colours at once. What the Red 40 rules say sets out the same Annex V statement for E129, which is often printed on the same packet.

Yellow 5 and Yellow 6 are different dyes

Yellow 5 and Yellow 6 are separate colour additives that often sit next to each other on a label. Yellow 6 is Sunset Yellow FCF, E110 in Europe, CAS 2783-94-0, and the US rules treat the two differently even though the EU and the FDA’s 2025 plan group them together.

A label listing both is reporting two additives, and a check for one says nothing about the other. Red dye 3 is the contrast case: a colour whose listing the FDA has actually revoked, which is what a federal ban looks like on paper.

Where Yellow 5 shows up, and how to find it

The FDA names confections, cereals, snack foods, beverages, condiments, baked goods and yogurt as the foods where Yellow 5 is typically used. Outside the grocery aisle it is also listed for drugs and cosmetics, including eye-area products.

1. Step 1

   Look for every name

   Yellow 5, FD&C Yellow No. 5, Yellow 5 Lake, tartrazine and E102 all point to the same additive. Imported packaging may print only the European names.

2. Step 2

   Read to the end of the list

   Colours are usually among the last ingredients, often after a phrase such as contains 2% or less of. Scanning the first few lines misses them.

3. Step 3

   Check medicines and supplements separately

   Drug labels carry tartrazine in the inactive ingredients or in a Precautions statement, not in the food-style ingredient list.

The ultra-processed food checker matches all of these names to one entry and shows the labelling note beside the match, so a pasted list returns the rules above rather than a bare flag.

What this page does not tell you

This page reports what regulators and legislatures have written and when. It does not assess what Yellow 5 does in any one person, and a clinician is the right person for a suspected reaction or a child’s restricted diet. The rules this site follows for food claims are set out in our food methodology, and the other colours are in the food additive guides.