Nicotine, given to animals, is extremely toxic. Why can humans smoke nicotine in cigarettes?
Well, when cigarettes are smoked, much of the nicotine is “vaporized” (broken down), so the toxic effects are reduced. People smoke because of the calming, or (in some cases) energizing effects. Doesn’t it make sense that people who smoke for such effects are sacrificing their health? We do the same with food, but the toxic effects of nicotine are much greater than the toxic effects of food.