Jean Althen (Hovhannès Althounian) (1709–1774) was an Armenian agronomist, who developed in France the cultivation of madder.
Although the plant had been present in the region before his arrival, it was Althen who developed its cultivation, turning it into an industry.
In 1754, he arrived in Avignon where he started experimenting with the cultivation of madder. Associated with a local landlord, Clauseau Aïné, he produced a crop of 2500 kg (5500 lbs) in 1769. Poor business decisions led to financial problems, and he died in poverty in 1774.
A French commune, Althen-des-Paluds, is named after him, as well as statues and streets in several cities of the south of France.