Angostura Bitters, often simply referred to as "bitters", is a flavoring agent made of water, alcohol, gentian root and other vegetable flavoring extracts by House of Angostura in Trinidad and Tobago. It is the most popular brand of bitters today. It is not made using the bark of the medicinal plant Angostura trifoliata; instead it was named after the Venezuelan city of Ciudad Bolívar, which used to be called Angostura.
The recipe was developed by Dr. Johann Gottlieb Benjamin Siegert, a German who served as Surgeon General in Simon Bolivar's army in Venezuela. The product was first sold in 1824.