North American plant with white or yellow flowers, the root of which was formerly used to treat abdominal pain

North American plant with white or yellow flowers, the root of which was formerly used to treat abdominal pain, The letters so far.


-O-I-R-O-

North American plant with white or yellow flowers, the root of which was formerly used to treat abdominal pain
Colicroot


Aletris farinosa L. (Liliaceae)