Corydalis ambigua is a tuberous early flowering east Asian flowering plant species. Its exact native range is obscure due to taxonomic confusion. It is one of the sources of the drug tetrahydropalmatine. Corydalis ambigua contains a variety of alkaloids including corynoline, acetylcorynoline d-corydalin, dl-tetrahydropalmatine, protopine, tetrahydrocoptisine, dl-tetrahydrocoptisine, d-corybulbine and allo-crytopine.