Introduction:
Tobacco smoking is acknowledged to be the most dangerous risk factor for many diseases. Tobacco enters the organism through the oral cavity. Here, both local and systemic effects of smoking are visible. One of many clinical symptoms caused by smoking is ‘‘diagnostic masking.’’ The World Health Organization has recognized nicotine addiction as a chronic and recurring disease which requires a comprehensive therapy. A dentist can be the first person who begins such a therapy.

Aim:
To present the effect of smoking on the condition of the oral cavity with reference to its masking influence and to promote an anti-nicotine attitude.

Material and methods:
This article is based on a review of the medical literature.

Results and discussion:
Making patients aware of the negative effects of nicotine on one’s organism is more difficult if they do not notice or experience negative symptoms of smoking.

Conclusions:
The hazards associated with tobacco smoking have been known for a long time and confirmed with research results. The so-called ‘‘masking symptoms’’ should not escape a physician’s attention. A lack of reddening, swelling and bleeding of the gums during probing in smoking patients does not prove that they do not suffer from a periodontal disease. The presence of lesions typical of smoking in the oral cavity does not mean they should not be differentiated from diseases which pose threat to life and health. Thus it is indispensable to perform additional diagnostic procedures to avoid hypodiagnosis. Numerous unfavorable consequences of cigarette smoking which occur in the oral cavity and elsewhere should be presented as warnings and posted on tobacco products’ packaging.