Tartrazine is a synthetic lemon yellow azo dye primarily used as a food coloring.

It serves as a dye for wool and silks, a colorant in food, drugs and cosmetics and an adsorption-elution indicator for chloride estimations in biochemistry.

Tartrazine was discovered in 1884 by Swiss chemist Johann Heinrich Ziegler, who developed the yellow azo dye in the laboratories of the Bindschedler'sche Fabrik für chemische Industrie in Basel (CIBA).

Products containing tartrazine commonly include processed commercial foods that have an artificial yellow or green color, or that consumers expect to be brown or creamy looking.

[14] It is not clear how many individuals are sensitive or intolerant to tartrazine, but the University of Guelph estimates that it is 1 to 10 out of every ten thousand people (0.01% to 0.1% of the population).

[18][19] Rumors began circulating about tartrazine in the 1990s regarding a link to its consumption (specifically its use in Mountain Dew) and alleged adverse effects on male erectile function, testicle and penis size, and sperm count.

[25] The United States requires the presence of tartrazine to be declared on food and drug products (21 CFR 74.1705 (revised April 2013), 21 CFR 201.20) and also color batches to be preapproved by the United States Food and Drug Administration (FDA).

[14] As part of these regulations, the FDA requires that the Precautions section of prescription drug labels include the warning statement, "This product contains FD&C Yellow No.

[18] However, in 2009 the EFSA re-evaluated the data at hand and determined that "the available scientific evidence does not substantiate a link between the color additives and behavioral effects.

"[18][30] Tartrazine is among six artificial colors for which the European Union requires products that contain them to be marked with the statement May have an adverse effect on activity and attention in children.

)[33] In response to concerns about the safety of certain food additives, the UK FSA commissioned a study by researchers at Southampton University of the effect of a mixture of six food dyes (Tartrazine, Allura Red, Ponceau 4R, Quinoline Yellow WS, Sunset Yellow and Carmoisine (dubbed the "Southampton 6")) and sodium benzoate (a preservative) on children in the general population, who consumed them in beverages; the study published in 2007.