-- Posted by utheh at 12:54 pm on July 10, 2009 Does anyone know approximately how much quinine there is per cup of tonic water? -- Posted by Chasey at 12:55 pm on July 10, 2009 i dont, im sorry -- Posted by Dexter Ward at 12:57 pm on July 10, 2009 Something like 80 mg per liter at most in the USA. That's very low compared to the dose needed to treat malaria. Edit I did liter to cup conversion and its like 19 mg per cup at most in the USA if that helps.