Drug is any substance (with the exception of food and water) which, when taken into the body, alters the body’s function either physically and/or psychologically. Drugs may be legal (e.g. alcohol, caffeine and tobacco) or illegal (e.g. cannabis, ecstasy, cocaine and heroin). Following is 10 most dangerous drugs that we must not try.. 10-erimen 5 9-ecstasy 8-ketamime 7-Ice 6-Heroin 5-cocaine 4-marijuana 3-LCD 2-opium 1-magic mushroom