Smoking can cause long-term negative effects on the body, including heart disease, cancer, and diabetes. Whether smoked or chewed, tobacco is dangerous to your health. Tobacco products contain unsafe substances, from acetone and tar to nicotine and carbon monoxide. The inhaled substances can affect your lungs and the other organs in your body. Smoking can lead to ongoing complications and long-term effects on your body systems. While smoking can increase your risk of certain health conditions over years, like glaucoma, cancer, and issues with blood clotting, some of the bodily effects happen immediately.