As we all know, cigarettes contain nicotine. This is the addictive compound that gets the most attention when cigarettes and smoking are discussed. What is perhaps less well known, is that over 4000 chemicals are released from a lit cigarette. Although the exact amount of each chemical varies by brand, the chemicals are there in some amount in almost all cigarettes. Many of these chemicals have detrimental health effects for anyone exposed to them. Obviously, detailing them all here is not possible. I will mention about a dozen (give or take) to give you an idea of what's in that smoke.
Some of the chemicals are known carcinogens (cancer-causing agents). These include: nitrosamines, benzo(a)pyrene, urethane, and toluidine. Chemical carcinogens require extra protective clothing for laboratory personnel who work with them. Yet smokers expose themselves (and others) every time they light up.
There are even metals in cigarettes. For example:
Lead: Everyone knows that lead has been removed from paint because it is very dangerous to children, who not only tend to absorb more than adults, but are more sensitive to its effects. Adults with high lead levels in their blood may have high blood pressure, nerve disorders, muscle pain and even fertility problems.
Copper: Smokers have about twice as much of this metal in their bodies as do non-smokers. Chronic (long-term) exposure can result in a build-up in the kidneys, causing kidney disease. It also shows signs of being a carcinogen, although the evidence is not conclusive.
Mercury: Chronic exposure is known to cause adverse effects on mood, behavior and memory. More specifically, irritability, tiredness, sleeplessness, tremors and damage to the nerves in the arms and legs have been reported.
Aluminum: Chronic exposure can cause, shortness of breath, weakness, and cough.
Some other chemicals, in no particular order, and their health effects:
Acetone: Inhalation can cause dizziness and headache.
Ammonia: Chronic exposure to ammonia can have permanent effects on the lungs, nose, and eyes, including inflammation of the airways and irritation of the eye membranes.
Arsenic: More commonly thought of as a poison that causes death when ingested (swallowed), chronic inhalation of arsenic results in irritation of the skin and mucous membranes. It is also strongly liked to lung cancer.
Butane: Short-term exposure can cause nausea, vomiting, headache, drowsiness, and even suffocation, convulsions, or coma.
Carbon Monoxide: Everyone knows this one, it's the part of the car exhaust that kills when someone locks themselves in the garage with the car running. Chronic exposure can cause severe headaches, dizziness, tiredness, and nausea.
DDT: This chemical has been banned for use in the United States since 1972. Exposure to high quantities and cause headaches, nausea and convulsions.
Formaldehyde: Inhalation causes eye, nose and throat irritation. High levels can cause wheezing, coughing, chest pain and bronchitis.
Hydrogen Cyanide: Most people are aware that cyanide is poisonous when swallowed. Inhalation can also cause headache, dizziness, chest tightness, eye irritation and itchy skin.
Toluene: Inhalation can result in fatigue, sleepiness, headaches and nausea, as well as cardiac arrhythmia (irregular heartbeat).
Naphthalene: This material is better know as mothballs. We all know how smelling those makes you feel, i.e., headache and even nausea. Some other symptoms of acute (short-term) exposure are vomiting, diarrhea, and confusion. Chronic exposure has been known to cause cataracts, as well as inflammation of the lung and nasal passages.
As you can see, nicotine is not the only (or even the most dangerous) component of that cigarette.