It has light green pinnate leaves and sheafs of pink or violet flowers.

The rotenoids deguelin, dehydrodeguelin, rotenol, rotenone, tephrosin and sumatrol can be found in I.

They are soaked in water and fermented in order to convert the glycoside indican naturally present in the plant to the blue dye indigotin.

The precipitate from the fermented leaf solution is mixed with a strong base such as lye.

Marco Polo (13th century) was the first European to report on the preparation of indigo in India.