My clinical experience with patients who are attempting to stop smoking indicated that most are unable to succeed for whatever reasons. My personal feeling is that it simply requires sheer will power for the first month, forcing yourself to not smoke as though your life depended upon it, which it does. After that, the physical addiction symptoms will be gone, and the rest is largely psychological. People tend to revert to smoking after quitting when facing stressful situations, and it is impossible to avoid stress forever. Herbs can help a little, but they cannot solve the problem. If I sound discouraging, it is because I am. Jim Duke is a bit more encouraging.
To reduce craving during withdrawal, and to handle situations of post-smoking stress, use calming nervines like milky oat seed, kava root and skullcap tincture. Lobelia herb (Lobelia inflata) contains an alkaloid called lobeline, which has a chemical structure similar to nicotine (Flammia et. al., 1999), and has been reported by some practitioners to mask the withdrawal symptoms of nicotine addiction. Consult a professional before using this herb.
To repair damage to the lungs from smoking, if it is not too late, use the same herbs and methods of differentiation mentioned directly below for chronic respiratory problems. Emphasize herbs that reduce lung inflammation combined with herbs that soothe and nourish. Using about 1,500 mg of turmeric root per day can help prevent damage, and one company has created a product based on this idea.