Species of Indigofera were cultivated in East Asia, Egypt, India, and Peru in antiquity. The earliest direct evidence for the use of indigo dates to around 4000 BC and comes from Huaca Prieta, in contemporary Peru.Pliny the Elder mentions the Indus Valley Civilization as the source of the dye after which it was named. It was imported from there in small quantities via the Silk Road.

The Ancient Greek term for the dye was ("Sindhi dye"), which, adopted to Latin as indicum and via Portuguese gave rise to the modern word indigo.
Spanish explorers discovered an American species of indigo and began to cultivate the product in Guatemala. The English and French subsequently began to encourage indigo cultivation in their colonies in the West Indies.
Blue dye can be made from two different types of plants: the indigo plant, which produces the best results, and from the woad plant Isatis tinctoria, also known as pastel.For a long time woad was the main source of blue dye in Europe. Woad was replaced by true indigo as trade routes opened up, and both plant sources have now been largely replaced by synthetic dyes.