Tonic water is a carbonated beverage known for its distinct bitter and slightly sweet taste. It is a popular mixer in cocktails, most notably in the classic Gin and Tonic. Tonic water gets its unique flavor from the addition of quinine, a bitter compound derived from the bark of the cinchona tree. Originally developed as a way to prevent and treat malaria, quinine gives tonic water its characteristic taste. In addition to being a mixer, tonic water can also be enjoyed on its own as a refreshing and effervescent beverage. It adds a crisp and tangy element to cocktails and is a staple ingredient behind the bar.