text: Use Tonic water is often used as a drink mixer for cocktails, especially gin and tonic. Vodka tonic is also popular. Tonic water with lemon or lime juice added is often known as bitter lemon or bitter lime. It is popular for its signature bitter but sweet taste. Another use of tonic water is in coffee. The espresso and tonic was created in Helsingborg, Sweden, at Koppi Roasters after a staff party where they mixed tonic water, syrup, and an espresso. Since 2007, the drink has grown in popularity in Scandinavia, Europe, and the United States.
  Negative effects
  Tonic water is known to cause fixed eruptions, which is a type of skin reaction to drugs, due to the quinine content. Various scientific journals have reported that repeated intake of tonic water can cause fixed eruptions with varying severity, with one reporting the onset of Stevens-Johnson syndrome. The cases of fixed eruptions were seen after the patients drank tonic water, by itself or mixed with gin. Some symptoms of fixed eruptions include pigmented macules, high fever, erythematous plaques, and bullae.
  Fluorescence
  The quinine in tonic water will fluoresce under ultraviolet light. In fact, quinine will visibly fluoresce in direct sunlight against a dark background. The quinine molecules release energy as light instead of heat, which is more common. The state is not stable and the molecules will eventually return to a  ground state and no longer glow.