Hematoxylin is a naturally occurring chemical used as the basis of a dye in laboratories throughout the world to stain nuclei in microscope slide preparations. This chemical is extracted from the logwood tree Hematoxylon campechianum and was discovered by Spanish explorers to the Yucatan in 1502. A vigorous trade soon developed related to growing and preparing hematoxylin for use in dyeing fabrics in Europe. In the mid 1800s, amateur microscopists first used hematoxylin to stain cellular components. Later scientists developed a wide range of techniques to demonstrate different cellular components. Hematoxylin remains the most popular nuclear stain in histology. This paper briefly describes the history of hematoxylin production and use in histology.