Last reviewed: 11 May 2026
Synthetic Yellow-Orange Dye with Hyperactivity Concerns
UK products containing E110 must carry the wording "May have an adverse effect on activity and attention in children." This is mandatory, not editorial — it applies to six synthetic azo dyes (E102, E104, E110, E122, E124, E129) flagged in the 2007 Southampton Study.
E110 is Sunset Yellow FCF, a synthetic yellow-orange azo dye originally developed from coal-tar chemistry.
Also known as: Yellow 6 (US name), FD&C Yellow No. 6, Orange Yellow S, C.I. Food Yellow 3.
It's used because it's a cheap, heat- and light-stable colour that gives an "orange" appearance to products that contain no natural orange ingredient.
The 2007 Southampton Study (published in The Lancet) tested E110 alongside five other dyes — E102, E104, E122, E124, E129 — and the preservative E211 (sodium benzoate), in children aged 3 and 8–9. The study reported increased hyperactivity and reduced attention scores, with effects observed across the general child population, not only children with ADHD diagnoses.
The FSA and EFSA reviewed the findings. Since 2010, UK and EU food law has required a warning label on any food product containing one of these six dyes:
"May have an adverse effect on activity and attention in children."
The dyes are commonly referred to as the Southampton Six.
E110 is an azo dye structurally related to salicylates. The published clinical literature describes cross-reactivity in people sensitive to aspirin (acetylsalicylic acid) and other NSAIDs (ibuprofen, naproxen) — with estimates putting the cross-reactivity rate among aspirin-sensitive people at roughly 20–30%. Reported reactions include:
This is the strongest non-Southampton finding on E110, and the reason allergy and asthma specialists routinely advise sensitive patients to avoid the dye.
Azo dyes like E110 are reduced by gut bacteria to aromatic amines. The long-term toxicological significance of these breakdown products under chronic dietary exposure remains under investigation; the published literature is mixed and the regulators have not closed the question.
Long-term rodent studies have reported kidney and adrenal tumours at very high doses of E110. Translating those signals to humans at typical dietary intake is uncertain. The FSA, EFSA and FDA position is that the established ADI of 4mg/kg body weight per day does not present a meaningful cancer risk at normal consumption — while keeping the dye under continued review.
UK / EU: approved with an ADI of 4mg/kg body weight per day. The Southampton warning is mandatory on any product containing E110.
US: FDA approved as Yellow 6. No warning label required.
Norway: was banned until 2000; now permitted with restrictions.
For the general child population the regulator's response was the warning label rather than a ban — parents who want to act on the Southampton findings can use the FSA warning as a shopping signal.
Manufacturers replacing E110 typically reach for plant-derived colours:
None carry the Southampton warning.
Look for "E110", "Sunset Yellow FCF", or "colour: E110" in the ingredient list, and look for the FSA warning sentence under the ingredients. The warning is small print, but is mandatory.
Scan UK barcodes to spot E110 and the rest of the Southampton Six in seconds. We surface the FSA warning every time it appears on a pack.
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