Q.01

What is Yellow 5?

"Yellow 5" is FD&C Yellow No. 5, a synthetic yellow azo dye better known as tartrazine. It is CAS 1934-21-0, C.I. 19140, E102 in the EU and INS 102 in Australia/New Zealand. In the US it is permanently listed as a color additive for foods, drugs and cosmetics, and every batch must be certified by the FDA [1][2].

Approach: I checked the FDA's Regulatory Status of Color Additives list (edition last updated 08/14/2026) and FSANZ's table comparing US and EU food additive permissions.

Identity [1]

  • Chemical name: trisodium 4,5-dihydro-5-oxo-1-(4-sulfophenyl)-4-((4-sulfophenyl)azo)-1H-pyrazole-3-carboxylate.
  • Other names: tartrazine, Acid Yellow 23, C.I. Food Yellow 4, Food Yellow No. 4, D&C Yellow No. 5, Yellow Lake 69.

US status

  • Listing regulations: 21 CFR 74.705 (food), 74.1705 (drugs), 74.2705 (cosmetics) and 82.705. It is also referenced in 21 CFR 178.1010 and 178.3297 [1].
  • Permitted uses: foods generally, ingested drugs, externally applied drugs, cosmetics generally, and eye-area use, lakes included. Eye-area use was added by a final rule on 11/29/1994 (59 FR 60893) [1].
  • Batch certification: each batch must be analysed and certified by the FDA before use. This applies to imported products as well as US-made ones. The aluminum lakes for drug and cosmetic use are permanently listed in 74.1705 and 74.2705 [1].
  • Labelling: the FDA list includes rules on labelling foods and ingested drugs that contain it (final rule 06/26/1979, 44 FR 37212) [1].
  • History: its first food use dates to a 1916 USDA Food Inspection Decision [1].

Elsewhere: FSANZ's table shows it as tartrazine (INS 102) under the Food Standards Code. The same table gives its US basis as 21 CFR §74.705 and its EU basis as Regulation (EC) No 1333/2008 [2].

I can pull the E102 conditions of use (food categories and maximum levels) from the EU food additives regulation next if that would help.

Q.02

Is it bad for you?

At permitted levels, regulators consider tartrazine (Yellow 5 / E102) safe for most people, but it has two known caveats. A small fraction of people get intolerance reactions to it, sometimes at doses within the acceptable daily intake (ADI). And because it has been linked to hyperactivity in children, EU labels must carry a warning. EFSA's 2009 re-evaluation saw no reason to change the ADI of 7.5 mg/kg bw/day and found that estimated intakes stay below it [3].

Approach: I looked at EFSA's scientific opinions and its OpenFoodTox hazard database, the EU food additives regulation (1333/2008), 21 CFR 74.705, and the classifications companies have notified to ECHA's C&L Inventory. I did not open the JECFA monograph itself; its 2016 ADI comes from EFSA's own summaries.

General toxicity

  • EU ADI: 7.5 mg/kg bw/day. This was first set by JECFA (1966) and the SCF (1975, 1984), and EFSA confirmed it in 2009 [3][4].
  • JECFA ADI: 0-10 mg/kg bw. JECFA raised its ADI to this in 2016. It is based on a no-effect level (NOAEL) of 984 mg/kg bw/day for reduced body weight in a chronic rat study, with a 100-fold safety factor [5][6].
  • Genotoxicity and cancer: EFSA's 2009 endpoint summaries record it as not genotoxic, not mutagenic and not carcinogenic [7][8].
  • Absorption: less than 5% is absorbed when swallowed, and it does not build up in the body [9][10].

Caveat 1: intolerance in sensitive people

  • EFSA 2009: tartrazine can trigger intolerance reactions in a small fraction of people, and sensitive individuals may react at doses within the ADI [3].
  • EFSA 2010 opinion on azo colours:
    • Reported reactions include urticaria (hives), angioedema (swelling), wheezing and leukoclastic vasculitis.
    • Tartrazine intolerance is estimated at under 1% of people with food-induced urticaria and angioedema.
    • Severe reactions are unlikely at current use levels [11].
  • Labelling: the ANS Panel said its presence must be clearly labelled on foods and medicines so that intolerant people are informed [12].
  • US rule: FDA rules require foods containing it, including butter, cheese and ice cream, to list "FD&C Yellow No. 5" by name in the ingredients [13].

Caveat 2: hyperactivity in children

  • The McCann (Southampton) study, 2007: children aged 3 and 8-9 who ate mixtures of four synthetic colours plus sodium benzoate showed increased hyperactivity [14].
  • EFSA's view: the findings could not be used as a basis for changing the ADI [3].
  • EU warning label: EU law still requires foods containing E102 (along with E104, E110, E122, E124 and E129) to state "may have an adverse effect on activity and attention in children". Article 24 and Annex V of Regulation 1333/2008 set this out. Two exemptions apply: health marking on meat or decorative colouring on eggshells, and drinks over 1.2% alcohol [15][16].

Handling the raw dye (workplace, not diet)

  • EFSA feed panel: breathing in tartrazine dust is regarded as hazardous, and tartrazine is considered a skin sensitiser [5].
  • No EU harmonised classification: there is no CLP Annex VI entry.
  • Industry self-classifications (C&L Inventory):
    • About 75% of notifications do not classify it.
    • About 21% classify it as Skin Sens. 1 (H317) and Resp. Sens. 1 (H334) [17][18][19].

I can check next whether it carries a drug-labelling warning in the US or EU, or compare its status in other jurisdictions.

Q.03

Does it need a warning label in the UK?

Yes. In the UK, foods containing tartrazine (E102) must carry the statement "E102 [or tartrazine]: may have an adverse effect on activity and attention in children." This comes from Article 24 and Annex V of the UK (retained) version of Regulation (EC) No 1333/2008. The wording is the same as the EU rule.

Approach: I checked the GB approved additives and E-numbers list, then the UK text of Regulation 1333/2008 on legislation.gov.uk and the Food Standards Agency's food additives guidance. The GB list confirms E102 is approved but does not cover labelling, so the labelling rule comes from those official web pages.

Approval status

  • E102 tartrazine is on the GB list of approved additives as a colour [20].

The legal requirement (Article 24, Annex V, UK version)

  • Article 24: food containing any colour listed in Annex V must show the extra information set out in that Annex. Under the UK text, Annex V can be changed by measures "prescribed by the appropriate authority", not by the European Commission.
  • Colours covered: six colours, which are E102 tartrazine, E104 quinoline yellow, E110 sunset yellow, E122 carmoisine, E124 ponceau 4R and E129 allura red.
  • Wording: "'name or E number of the colour(s)': may have an adverse effect on activity and attention in children."
  • Exemptions:
    • colours used for health marking on meat products, or for stamping or decorative colouring on eggshells;
    • drinks containing more than 1.2% alcohol by volume.
  • Changes since Brexit: the Annex V text reflects the amendment made by Regulation (EU) No 238/2010 (applying from 20 July 2010). The UK has made no change to the colour list or the wording since 31 December 2020.

FSA guidance (Food additives, published 9 January 2018)

  • The guidance confirms the same six colours and the same warning. It explains that the rule follows research showing these colours could increase hyperactivity in some children.
  • It covers England, Wales and Northern Ireland. Scotland is outside it because Food Standards Scotland issues its own guidance. I did not open the Food Standards Scotland pages.

Northern Ireland: the EU version of Article 24 and Annex V sets the same requirement and the same exemptions [15][16]. So the label wording is the same whether the EU or the UK text applies there.

I can also check whether UK medicines containing tartrazine must carry an excipient warning, if that's useful.

Q.04