Lariam is used to treat malaria and to help prevent you from catching malaria. Malaria is a life threatening disease and a major health risk for travellers visiting tropical countries. It occurs when small parasites are passed from one person to another by the bites of certain mosquitoes. Lariam is especially useful if you are travelling to countries where there is a type of malaria which is particularly difficult to treat. No single medicine is effective against all malaria parasites. The choice of a particular medicine depends on the sensitivity of the malaria parasites found in the area to be visited. Your doctor will advise you whether Lariam is suitable for the area to which you wish to go.