Nicotine patches are currently marketed as a cure for smoking. What they actually are, so far as I can tell, is an alternative delivery system for the same drug. Insofar as what smokers really want is the effect of nicotine the patches may well succeed in getting smokers to quit, but they cure an addiction to cigarettes only in the sense that whiskey cures for an addiction to wine.
Considered as a substitute, they have two big advantages over cigarettes. Since they get nicotine to the blood stream without going through the lungs, they should have fewer adverse health effects; there is no obvious reason why the use of nicotine patches would cause lung cancer. And they eliminate both the (somewhat controversial) medical effect of second hand smoke and the unpleasantness that nonsmokers experience from the smell of tobacco. The user of a nicotine patch may perhaps harm his own health, but he should have very little effect on those around him.
This may be an early and interesting example of an alternative approach to the problems associated with both legal and illegal drugs. The conventional solution is to stop people from using drugs. The alternative is to find ways of providing the effects drug users want while minimizing undesirable side effects, on themselves and others.