Among other things, it causes cancer of the mouth, tongue, throat, esophagus and lungs. It has also been implicated in a variety of other ailments, including liver disorders. Finally, many of the ingredients are known to be poisonous.
All of tobacco's effects are negative, and here are some of the ones that I know: yellowing teeth, wrinkly skin, everyone knows the horrible effects on the lung, rotting gums from chewing tobacco,...