E104

Quinoline Yellow

Last reviewed: 11 May 2026

Synthetic greenish-yellow dye — Southampton Six, banned in the US

What is E104?

E104 is Quinoline Yellow, a synthetic greenish-yellow dye. Chemically it's a quinophthalone dye, not a true azo dye like most of the other Southampton Six — but it sits in the same UK warning rule. It's derived from petroleum.

Also known as: Quinoline Yellow WS, Food Yellow 13, C.I. Food Yellow 13, China Yellow.

It's used because it's stable in acid (good for citrus flavours), cheap, and gives a sharp greenish-yellow tone that natural pigments struggle to match.

Where you'll see E104 on a UK label

Drinks

• Lemon and lime soft drinks
• Flavoured cordials and squash
• Some energy drinks

Sweets and desserts

• Lemon sweets and sherbet
• Ice lollies
• Some boiled sweets

Other foods

• Smoked haddock and smoked fish (traditional yellow colouring)
• Scotch eggs
• Some pickles and packet soups

Non-food uses

• Medicines — tablets and syrups
• Cosmetics

The Southampton Study and the UK warning rule

The 2007 Southampton Study (published in The Lancet) tested E104 alongside five other dyes — E102, E110, 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 across the general child population, not just children with ADHD diagnoses.

Since 2010, UK and EU food law has required this warning on any 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.

Asthma and aspirin/NSAID cross-reactivity

The published clinical literature describes E104 as a trigger for asthma symptoms in a subset of people with aspirin-sensitive asthma. Reported reactions include:

• Bronchoconstriction in people with aspirin-induced asthma
• Hives (urticaria) and skin rashes
• Rhinitis — runny nose, sneezing
• Eczema flare in sensitive individuals

Allergy and asthma specialists routinely flag E104 to aspirin-sensitive patients.

Animal-study tumour signals

Long-term rodent studies have reported tumour signals at very high doses of E104. Translating those signals to humans at typical dietary intake is uncertain — the EFSA position on the ADI reflects continued review rather than a closed question. The low ADI (see below) sits well below most of the other Southampton Six.

Regulatory status

UK / EU: approved with an ADI of 0.5mg/kg body weight per day — notably lower than the other Southampton dyes (E110 sits at 4mg/kg, E102 at 7.5mg/kg). The Southampton warning is mandatory on any product containing E104.

US: the FDA has never approved E104 for food use. It's permitted only in externally applied drugs and cosmetics (D&C Yellow No. 10), not in food.

Australia and Japan: not approved for food use.

Norway: historically banned.

Who has the strongest reason to avoid E104

• People with aspirin-sensitive asthma — published trigger
• People with chronic asthma generally — precautionary
• Children with diagnosed ADHD — Southampton-study evidence
• People with aspirin or NSAID intolerance
• Anyone with chronic urticaria — case reports of worsened hives

Yellow alternatives on UK labels

Manufacturers replacing E104 typically reach for plant-derived colours:

• Curcumin (E100) — natural yellow from turmeric
• Riboflavin (E101) — vitamin B2
• Beta-carotene (E160a) — from carrots and other plants

None carry the Southampton warning.

Reading a UK label

Look for "E104", "Quinoline Yellow", or "colour: E104" in the ingredient list, and look for the FSA warning sentence under the ingredients. The warning is small print, but is mandatory. Imported US products will not carry E104 — it's not approved there for food use.

Last updated: 11 May 2026