Tonic water is a carbonated beverage that derives its somewhat
bitter taste from the addition of quinine, which also makes it glow
when exposed to UV light. It usually is flavored with lemon or lime
and lots of sugar, and it often contains caffeine. This beverage is
frequently used in mixed cocktails, most famously in gin and tonic,
although vodka with tonic water also is popular. Tonic water also
can be used with sweet alcohols, such as vermouth, to produce a
balanced taste.
So delicious mixed beverage