The crossword solution for the term SUBSTANCE IN TOBACCO is NICOTINE, an 8-letter word. NICOTINE is a highly addictive stimulant found in tobacco products such as cigarettes, cigars, and chewing tobacco. It is a colorless, odorless liquid that is naturally produced in the tobacco plant. NICOTINE acts on the central nervous system and can cause a variety of physical and psychological effects, including increased heart rate, increased blood pressure, and increased alertness.