Nicotine is an alkaloid that is primarily found in the tabaco plant, Nicotiana tabacum, as well as in low concentrations in other nightshade plants such as potatoes, tomatoes, and eggplants. It is formed in the roots of the tobacco plant and stored in the leaves, where it serves to protect the plant from being eaten by animals. Due to its strong insecticidal effect, nicotine was used as a pesticide in former times. This usage of the alkaloid was gentle on the plants and biodegradable. Although nicotine is sometimes still used as a pesticide in foreign countries, due to its high toxicity, the European Union banned this usage of nicotine in the year 2010.

At high concentrations, nicotine causes dizziness, nausea, and vomiting. At higher doses, it can have crippling effects and even lead to death. For adults, the lethal dose of nicotine is estimated to be 30-60 mg, which corresponds to a dose of 0.5-1.0 mg/kg bodyweight. For infants, even a dose of 10 mg nicotine is considered life-threatening, which is about the same amount contained in the average cigarette. In the year 2009, the European Food Safety Authority (EFSA) determined an Acceptable Daily Intake (ADI) and an Acute Reference Dose (ARfD), setting both at 0.0008 mg/kg bodyweight.