Background: A plant powder called "Maras powder" is widely used instead of cigarette smoking in the South-Eastern region of Turkey. It has been confirmed that this powder comprises tobacco Nicotiana rustica L. Methods: The aim of this study was to assess the effect of Maras powder and cigarette smoking on the PIS promotor hypermethylation. Twenty-two Maras powder users (Group I), 12 cigarette smokers (Group II), and 16 healthy controls who neither smoked nor used Maras powder (Group III)were included in the study. Hypermethylation of the P16 gene was examined using methylation-specific PCR (MSP) method in the blood of the three groups. Results: Aberrant PIS methylation was found in 7 of the 22 (31.8%) in Group I, in 3 of 12 (25%) in Group II, and in 1 of 16 (6.25%) in Group III. Conclusion: Maras powder may be as harmful as cigarette smoking, leading to hypermethylation in PIS and warrants detailed studies on this subject. (C) 2009 Elsevier Ltd. All rights reserved.