butter yellow

but·ter yel·low

(bŭt'er yel'ō), [C.I. 11160] A fat-soluble yellow dye (MW 225) that has hepatic carcinogenic action in experimental animals; used as an indicator of pH (red, at pH 2.9, yellow at pH 4). Synonym(s): dimethylaminoazobenzene, methyl yellow

butter yellow

A fat-soluble yellow dye formerly used as a food additive, which proved to be a liver and bladder carcinogen in rodents and is no longer used in food.
Toxicity
Hepatomegaly, liver and kidney dysfunction, contact dermatitis, cough, wheezing, dyspnoea, bloody sputum, urinary frequency, haematuria, dysuria, possible occupational carcinogen.