Research background. The current commercial scenario indicates an increase in the demand for natural dyes. Compared to synthetic dyes, natural ones have the advantage of being sustainable, making them of great interest for the food and cosmetic industries. The development of new natural dyes is necessary, as well as the carrying out of complementary research regarding the existing ones. Experimental approach. The present study aimed to characterize the chemical and physicochemical characteristics of the dehydrated endocarp of the genipap (Genipa americana) fruit, as well as performing the relevant stability and cytotoxicity tests. The chemical characterization was performed by LC/MS/MS analyses. The stability studies were carried out by spectrophotometry and cytotoxicity assays using cell culture and fluorometric methods. Results and conclusions. After dehydration and milling of the fruit's endocarp, a powder was obtained, which with 20 % water was used to extract the dye. Five compounds were elucidated using HPLC-MS and confirmed the presence of the geniposide as its main compound. Via the X-ray diffraction test and electron microscopy analysis, it was possible to describe the powder obtained as being amorphous and of porous structure with a variable size, respectively. The thermogravimetric analysis indicated a maximum loss of 61 % mass after exposure to a temperature range of 240 °C to 760 °C. The obtained blue dye showed to be stable in the absence of light, at room temperature and presented neutral pH. In the cytotoxicity assay, 95.05±1.33 % of viable human fibroblast were observed after exposure to this dye. The genipap fruit can be a viable alternative for the obtention of natural blue dye, since it is easy to obtain and has very low toxicity for food, pharmaceutical or cosmetic industries. Novelty and scientific contribution. This study demonstrates for the first time the physicochemical and biological properties of a natural blue dye from G. americana fruit.