20 calories per can. Lower in calories. Fever-tree refreshingly light premium indian tonic water is 57% fewer calories than fever-tree premium indian tonic water. Made with natural flavors including natural quinine. No artificial sweeteners. Drinks international 2019: no.1 best selling tonic water as voted by the world's best bars. If 3/4 of your drink is the mixer, mix with the best. We believe a spirit is only as hood as the mixer it's paired with. That's why at fever-tree, everything we do starts and ends with taste. In our quest for the perfect tonic water, we spent days in the british library researching quinine sources before traveling to some of the most remote parts of the world, venturing as far as the democratic republic of the congo to find quinine of the highest quality.