What types of Rehmannia are there? A detailed guide to identification methods

Rehmannia is a perennial herb of the genus Rehmannia in the family Scrophulariaceae. There are mainly three types of Rehmannia: raw Rehmannia, prepared Rehmannia, and fresh Rehmannia. Let's learn how to tell these three apart!

Raw Rehmannia

[Shape] Mostly irregular lump-shaped or oblong, swollen in the middle and slightly narrower at both ends; some are small, elongated, slightly flattened and twisted, extremely shrunken, with irregular transverse curved lines; heavy, relatively soft and tough, not easy to break, glossy, sticky, 6-12 cm long, 3-6 cm in diameter.

[Color] Surface brownish-black or brownish-gray; cut surface brownish-black or jet black.

[Odor] Slight odor, slightly sweet taste.

Prepared Rehmannia

[Shape] Irregular slices and fragments, varying in size and thickness, glossy, highly sticky, soft yet somewhat tough in texture, not easy to break.

[Color] Surface jet black; cut surface jet black, glossy.

[Odor] Slight odor, sweet taste.

Fresh Rehmannia

[Shape] Spindle-shaped or strip-shaped, with a thin outer skin, curved wrinkles, transversely elongated lenticels, and irregular scars; part of the leaf has radiating veins, 9-15 cm long, 1-6 cm in diameter.

[Color] Surface light reddish-yellow; fleshly, cut surface pale yellowish-white, with visible orange-red oil dots.

[Odor] Slight odor, slightly sweet and slightly bitter taste.