Quinine Sulfate Tablets contain the anti-malarial drug Quinine Sulfate and are used to treat a type of Malaria known as falciparum malaria (malignant malaria). Malaria is a disease caused by infection with a malaria parasite. This is carried by mosquitoes, which flourish in tropical and subtropical countries. Human beings become infected as a result of being bitten by malaria carrying mosquitoes. Quinine sulfate has a relaxant action on skeletal muscle.