The Legal Dose of nicotine is 50 mg/kg for rats and 3 mg/kg for mice. 40-60 mg can be a lethal dosage for adult human beings. This makes it an extremely deadly poison, more toxic than many other alkaloids such as cocaine, which has a lethal dose of 1000 mg.
It is not believed that nicotine, on its own, promotes the development of cancer in healthy tissue and has no mutagenic properties. Its teratogenic properties have not yet been adequately researched, and while the likelihood of birth defects caused by nicotine is believed to be very small or nonexistent, nicotine replacement product manufacturers recommend consultation with a physician before using a nicotine patch or nicotine gum while pregnant or nursing.
However, nicotine and the increased acetylcholinic activity it causes had been shown to impede apoptosis, which is one of the methods by which the body destroys unwanted cells. Since apoptosis helps to remove mutated or damaged cells that may eventually become cancerous, the inhibitory actions of nicotine creates a more favorable environment for cancer to develop. Thus nicotine plays an indirect role in carcinogenesis. It is also important to note that its addictive properties are often the primary motivating factor for tobacco smoking, contributing to the proliferation of cancer.
