0.5-1.0 mg/kg
3. Nicotine. If you guessed # 3, you are correct. The lethal dosage for a 150 pound adult is 60 mg. The lethal dosage for # 2 is 75 mg and the lethal dosage for # 1 is 200 mg. In other words, nicotine is three times as toxic as arsenic and one and one half times as toxic as strychnine. Arsenic 2. Strychnine 3. Nicotine Standard textbooks, databases, and safety sheets consistently state that the lethal dose for adults is 60 mg or less (30–60 mg), leading to safety warnings that ingestion of five cigarettes or 10 ml of a dilute nicotine-containing solution could kill an adult. Indeed, more recent studies have shown that intravenous administration of up to 5 mg of nicotine, corresponding to 25 mg oral, i.e., 50 % of the allegedly lethal dose, led to only minor adverse effects, such as coughing and nausea (Henningfield et al. The LD50 of nicotine is 50 mg/kg for rats and 3 mg/kg for mice. 0.5-1.0 mg/kg can be a lethal dosage for adult humans, and 0.1 mg/kg for children.  This dose agrees well with nicotine toxicity in dogs, which exhibit responses to nicotine similar to humans (Matsushima et al. 1995). The mismatch between the generally accepted lethal dose and documented cases of nicotine intoxication raises the question for the genuine source of the 60-mg dose. Indeed, more recent studies have shown that intravenous administration of up to 5 mg of nicotine, corresponding to 25 mg oral, i.e., 50 % of the allegedly lethal dose, led to only minor adverse effects, such as coughing and nausea (Henningfield et al. Based on 20 % oral bioavailability of nicotine (Hukkanen et al. 2005) and assuming linear kinetics, an oral dose of 60 mg would give rise to a plasma concentration of about 0.18 mg/L. Indeed, more recent studies have shown that intravenous administration of up to 5 mg of nicotine, corresponding to 25 mg oral, i.e., 50 % of the allegedly lethal dose, led to only minor adverse effects, such as coughing and nausea (Henningfield et al. Nicotine Toxicology. By Dr Ananya Mandal, MD. Nicotine is a highly toxic chemical. While in rats, a dose of 50 mg per kg is lethal, in mice the median lethal dose is around 3 mg per kg weight. In humans, the median lethal dose is 0.5 to 1.0 mg/kg or around 40 to 60 mg in an average human. This low lethal dose makes nicotine more toxic than many other compounds including even alkaloids such as cocaine which has a median lethal dose of 95.1 mg per kg in mice Although an LD 50 of 0.8 mg/kg would implicate that the toxicity of nicotine is similar to or even higher than that of cyanide, fatal nicotine intoxications are relatively rare, and there are countless records of subjects who survived consumption of nicotine in amounts far higher than 60 mg (Larson et al. 1961). Indeed, more recent studies have shown that intravenous administration of up to 5 mg of nicotine, corresponding to 25 mg oral, i.e., 50 % of the allegedly lethal dose, led to only minor adverse effects, such as coughing and nausea (Henningfield et al. 1. Arsenic 2. Strychnine 3. Nicotine If you guessed # 3, you are correct. The lethal dosage for a 150 pound adult is 60 mg. The lethal dosage for # 2 is 75 mg and the lethal dosage for # 1 is 200 mg. In other words, nicotine is three times as toxic as arsenic and one and one half times as toxic as strychnine. Details. Created on Friday, 04 October 2013 21:17. Nicotine lethal dose in humans: a common argument by regulatory authorities, based on poor science. By Dr Farsalinos. I am sure everyone has heard the “magic number”: 60mg is the nicotine lethal dose in adults. τ his is a very low level, which would categorize nicotine as one of the most toxic substances available. I always wondered how the lethal dose level was defined, because everyone mentioned that the lethal dose was just theoretical and was never really tested. In animals the lethal dose may be from 3mg/kg in mice to 50mg/kg in rats, while a 60mg dose means a 0.8mg/kg in humans. A new LD50 for nicotine. Prof Graz does not suggest a new LD50 (median lethal dose) for nicotine, but an estimate would appear to be 750mg (halfway between his opinion of the lethal dose minimum and maximum). This is more than 12 times the current figure of 60mg. 
http://www.nicotinevictims.com/poison.htm http://link.springer.com/article/10.1007/s00204-013-1127-0/fulltext.html https://en.wikipedia.org/wiki/Nicotine_poisoning http://link.springer.com/article/10.1007/s00204-013-1127-0/fulltext.html http://link.springer.com/article/10.1007/s00204-013-1127-0/fulltext.html http://www.news-medical.net/health/Nicotine-Toxicology.aspx http://link.springer.com/article/10.1007/s00204-013-1127-0/fulltext.html http://www.nicotinevictims.com/poison.htm http://www.ecigarette-research.com/web/index.php/2013-04-07-09-50-07/132-nicotine-lethal-dose-in-humans http://www.ecigarette-politics.com/blog/nicotine-high-toxicity-myth-destroyed.html
how much nicotine is considered a lethal dose for humans