Recrystallization of demethylchlortetracycline

A process of recovering demethylchlortetracycline in the form of an inorganic acid salt thereof, from crude demethylchlortetracycline containing demethyltetracycline, comprises dissolving such crude demethylchlortetracycline in water by the addition of an alkali metal hydroxide to an aqueous slurry of the crude demethylchlortetracycline, filtering the solution to remove insoluble impurities and acidifying the filtrate with an inorganic acid, whereby the inorganic acid salt of demethylchlortetracycline substantially free from demethyltetracycline is precipitated. The alkali metal hydroxide is preferably added to a pH of 7-9 and is desirably sodium or potassium hydroxide. The filtrate is acidified to a pH of 0.5-1 and preferably 0.6-0.7. A specified inorganic acid salt of demethylchlortetracycline is the hydrochloride.