Cigarettes and their smoke contain harmful chemicals and carcinogens that can negatively impact a person's health. Smoking cigarettes increases the risk of cancer and tobacco-related diseases. Nicotine is the addictive substance in cigarettes that increases central nervous system activity, which controls organs like the heart and lungs. There are three types of smoke produced by cigarettes: mainstream smoke inhaled by smokers, and sidestream and thirdhand smoke that can impact non-smokers. Laws in the Philippines regulate the sale and use of tobacco products to protect public health.