Angostura Bitters

Angostura Bitters, Angostura bitters, often simply referred to as angostura, is a concentrated bitters for food and beverages made of water, 44.7% of alcohol, gentian  root, and vegetable flavoring extracts  by House of Angostura in Trinidad and Tobago.

The bitters were first produced in the town of Angostura (hence the name), and do not contain angostura bark..

Source: http://www.apakistannews.com/angostura-bitters-176921