A nicotine patch is a transdermal patch that releases nicotine into the body through the skin. It is usually used as a method to quit smoking. The first patch appeared in 1993.
Nicotine patches come in several dosages, for example, 21, 14, and 7 mg, so that users can phase out nicotine use. A cigarette delivers roughly 1 mg of nicotine, so someone who used to smoke a pack (20 cigarettes) per day or more could start with the "Step I" 21 mg patch, while someone who smoked less could start with "Step II". After several weeks at step I (6 is recommended), new non-smokers move on to step II (usually two weeks) and step III (two weeks)