Nicotine is an addictive substance that is absolutely non-carcinogenic, with an exciting effect similar to caffeine. It is found in several plants, including tobacco, and in smaller quantities in tomatoes and aubergines. Nicotine is produced naturally by plants to protect them from insects. Nicotine is extracted from tobacco plants and added to your liquids at a maximum strength of 20 mg/ml. Nicotine produces a hit, and the higher the dose, the greater the effect.