These medications -- called nicotine replacement therapy -- ease withdrawal symptoms and reduce the craving for nicotine, the National Cancer Institute (NCI) says. People trying to quit get a dose of nicotine, but not by smoking. Because it is cigarette smoke that harms the lungs, a smoker's health begins to improve while using this treatment. Smokers should use these drugs in smaller and smaller amounts for a few months, then finally stop using them. Two smoking-cessation aids do not contain nicotine -- Zyban and Chantix.

You also check with your doctor if you're pregnant or breast-feeding, or if you have unstable angina or have recently had a heart attack. The Agency for Healthcare Research and Quality says that smoking-cessation aids are fine for everyone except for people in these categories.

Nicotine replacement therapy is available without a prescription as a patch, gum, nasal spray, inhaler and lozenge, the NCI says. You should choose an aid that best fits your lifestyle and your need for nicotine. Other quit-smoking help is available, as well: counseling, hypnosis or acupuncture.

The inhaler resembles a cigarette and contains a cartridge. You can draw a small amount of nicotine into your mouth with each puff. The nicotine does not end up in your lungs, as it does in smoking, but is absorbed by the mucus membranes in your mouth and throat.

Each nasal spray contains a certain dose of nicotine. If you have a nasal or sinus condition, or allergies or asthma, you shouldn't use a nicotine nasal spray. This treatment should not be used by teenage smokers, according to the NCI.

The patches are available with different amounts of nicotine. Once you put the patch on your skin, you leave it on for 16 to 24 hours. As treatment progresses, you use a patch containing less nicotine. You shouldn't use a nicotine patch if you have skin problems or allergies to adhesive tape, the NCI says.

This treatment is a good choice if you crave having something in your mouth. The gum is available in 2 mg and 4 mg strengths. If you have a jaw joint disease, gum disease or peptic ulcer disease, you may not want to use nicotine gum, the NCI says. You also shouldn't use the gum if you have dentures or bridges. Nicotine gum also can be used along with the nicotine patch.

Zyban eases withdrawal symptoms and the urge to smoke, but it does not contain nicotine. Common side effects of this drug are dry mouth, difficulty sleeping, dizziness and skin rash, the NCI says. If you have a seizure disorder or an eating disorder, you should not use this drug. You also shouldn't use it if you use other medicines that contain bupropion hydrochloride.

Although patients should not smoke, if they do they shouldn’t really worry and should not remove their patch. It’s much more risky that patients will have one cigarette then give up on the replacement therapy, thinking they can’t do both.

Your doctor, dentist, pharmacist or other health provider can counsel you on quitting smoking. You can also call a "quitline," a toll-free number that connects you to a telephone counselor.