Nicotine

Nicotine is found in the leaves of tobacco plants. Like capsaicin, the flavour chemical in hot peppers that produces a burning sensation, it is an alkaloid. Tobacco plants use nicotine as a defence against insects and grazing animals.

Nicotine is highly toxic for humans. One cigarette contains about 1 mg of nicotine. If you ingested 50-60 mg of nicotine, you could die. But it’s not the nicotine that gives you cancer. That’s caused by tar and other toxins in cigarettes and cigarette smoke.

When you smoke, nicotine enters your body through your lungs. It is quickly absorbed into your blood and directly affects your nervous system. It is this immediate effect – both stimulating and relaxing – that is so addictive and makes it so hard to give up smoking.