The Food and Drug Administration regulates absinthe alcohol in the United States. It was prohibited for so long due to one particular component. The chemical thujone is present in various culinary plants, including tarragon, sage, and wormwood. Thujone is said to be the cause of absinthe's "added effect." The structure of thujone is remarkably similar to that of THC (tetrahyrdacannaboid). Because of this resemblance, some people believe the two chemicals have comparable effects on the brain.