In aqueous solution at low pH, methyl yellow appears red.
[4] Butter yellow was synthesized by Peter Griess in the 1860s at the Royal College of Chemistry in London.
It was in the 1930s that research led by Riojun Kinosita showed the link between several azo dyes and cancer, linking butter yellow to liver cancer in rats after two to three months exposure.
[7] In 1939, the International Congress for Cancer Research issued a recommendation for the banning of cancer-causing food dyes (including butter yellow) from food production.
dougan 豆乾) from Taiwan were found to have been adulterated with methyl yellow, used as a coloring agent.