Gardeniablue is widely used in Eastern Asia as anatural foodcolorant. To evaluate the genotoxic potential of gardenia blue, as well asgenipin, the natural starting material from which it is produced, a GLP-compliant test battery was conducted according to OECD guidelines. No evidence ofmutagenicityof gardenia blue was detected in a 5-strain bacterial reverse mutation assay, with or without metabolic activation; an equivocal response forgenipinoccurred inS. typhimuriumTA97a without metabolic activation. Inin vitromicronucleusandchromosome aberrationassays, genipin tested positive under some test conditions; however, gardenia blue tested negative in both assays. In combined micronucleus/comet assays conducted in male and femaleB6C3F1 mice, exposure to genipin at doses reaching toxicity (74 and 222mg/kgbw/day for males and females, respectively) or gardenia blue tested up to the limit dose (2000mg/kgbw/day) did not induce micronuclei in peripheral blood or DNA damage in several examined tissues. Modified ("reverse")comet assaysshowed no evidence of DNA crosslinking potential of either genipin, known to form crosslinks with othermacromolecules, or gardenia blue. Our results indicate that consumption of gardenia blue in food products does not pose a significant genotoxic concern for humans.