Alkanet is grown in the south of France and on the shores of the Levant. It has a dark red root of blackish appearance externally but blue-red inside, with a whitish core. The root produces a fine red colouring material which has been used as a cloth dye and to give colour to tinctures, vegetable oils, wines, varnishes, etc. It was often used to improve the appearance of poor grades of port and similar wines, and to give the appearance of age to port wine corks. It is commonly used today as a food colouring E103 (chrysoine resorcinol).
It was listed in the 1918 Dispensatory of the United States of America as a colouring agent.