Synonyms: 2-Carboxy-4-hydroxy-1,1-dimethylpyrrolidiniumhydroxide, inner salt, L-trans- (6CI); Betonicine (8CI); Pyrrolidinium,2-carboxy-4-hydroxy-1,1-dimethyl-, hydroxide, inner salt, (2S-trans)-;Achillein; Achilleine; Betonicin; Pyrrolidinium,2-carboxy-4-hydroxy-1,1-dimethyl-, inner salt, (2S-trans)-;trans-4-Hydroxyproline betaine