World Education, a group that promote literacy, have a resource for understanding the risks of tobacco, which claims:
Chemicals in cigarettes and cigarette smoke are known to cause not only cancer but also other serious health problems. Many of the chemicals are poisonous. If a person ate one pack of cigarettes, he/she would die.
Is that claim true for an average adult (say 70kg/154lbs)?
Note: I'm not smoker, and rather disgusted by cigarette smoke, and curious about their level of toxicity
In this answer, I do not prove that eating a pack of cigarettes is safe. (Please don't do it!)
However, I show that there is a common belief that a pack of cigarettes would contain enough nicotine to kill an adult is based on a urban legend. (That doesn't mean it is wrong, just that it hasn't been proven right.)
This is based on this article:
The author explains there is a commonly quoted toxic level:
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.
[Special Note: There are two claims here. One is about the lethality of 60mg of nicotine, which is challenged below. The other is that five cigarettes contains (only) 60mg of nicotine. I do not challenge this in this answer. @DavePhD has since added an answer that provides a good reference to refute this claim, which casts my conclusion in doubt. Please give consideration to his answer.]
However, the scientific literature doesn't support that 60mg is lethal. Instead:
The literature reports on fatal nicotine intoxications suggest that the lower limit of lethal nicotine blood concentrations is about 2 mg/L, corresponding to 4 mg/L plasma, a concentration that is around 20-fold higher than that caused by intake of 60 mg nicotine. Thus, a careful estimate suggests that the lower limit causing fatal outcomes is 0.5–1 g of ingested nicotine, corresponding to an oral LD50 of 6.5–13 mg/kg. This dose agrees well with nicotine toxicity in dogs, which exhibit responses to nicotine similar to humans
(Reminder: Not everyone responds the same way to a poison. "LD50" is a dose that is toxic enough to be a lethal dose to 50% of the population.)
If these figures are correct, eating a pack of cigarettes is not enough to kill 50% of the people who try it.
However, you might be someone who reacts more strongly than the median person or there may be other toxic ingredients that are in cigarettes that haven't been considered here, so this should not be read as a go ahead to eat cigarettes.
According to Nicotine Content of Domestic Cigarettes, Imported Cigarettes and Pipe Tobacco in Iran Addiction & Health 2012, volume 4, pages 28–35.
The amount of nicotine in each cigarette was from 6.17 to 12.65 mg (1.23 ± 0.15 percent of tobacco weight in each cigarette) in domestic cigarettes. It was between 7.17-28.86 mg (1.80 ± 0.25 percent of tobacco weight in each cigarette) for imported cigarette, and between 30.08- 50.89 mg (3.82 ± 1.11 percent) for the pipe nicotine.
So if for example a given cigarette has 25mg of nicotine, and there are 20 cigarettes per pack, that is 500 milligrams of nicotine.
Yes, this is enough to be fatal: https://chemistry.stackexchange.com/questions/23881/would-nicotine-27g-per-1-5ml-be-lethal :
According to the US Center For Disease Control (CDC), The fatal human dose has been estimated to be about 50 to 60 mg.
However, the recent article How much nicotine kills a human? Tracing back the generally accepted lethal dose to dubious self-experiments in the nineteenth century Arch Toxicol. 2014; 88(1): 5–7 attempts to debunk this statement and concludes:
overwhelming data indicat[es] that more than 0.5 g of oral nicotine is required to kill an adult.
For more information, see Tobacco and cigarette butt consumption in humans and animals, which distinguishes between addicted and "non-addicted" persons. In other words, if you have never consumed tobacco before you will be more sensitive.
According to Case closed in Fort Plain liquid nicotine death, a boy died from ingesting a portion of a solution originally containing 100 mg of nicotine.
Also, in Two UK suicides using nicotine extracted from tobacco employing instructions available on the Internet Forensic Science International volume 199, pages e9-e13.
Deaths have been reported from the ingestion of 30 g tobacco, the infusion of 15–20 g of tobacco, an enema of 8 g of tobacco, and 0.8 g of snuff... Nicotine-related fatalities have occurred from a variety of causes: ingestion of salads containing wild tobacco leaves; boiled tobacco water enemas for intestinal parasites; ingestion of concentrated nicotine-based pesticide formulations; administration of multiple nicotine transdermal patches; oral ingestion of tobacco eluate (concentrate); smoking cigarettes containing crystals of nicotine tartrate; and nicotine solution mixed with alcohol.
A typical pack of cigarettes has about 20 grams of tobacco, but the amount varies.
The other answer already indicated that the nicotine in a cigarette is probably not enough to kill a person when ingested, but the referred paper actually links to a documented case of someone who ate cigarettes (including all relevant toxins).
Here is the relevant part of the conclusion:
In spite of the ingestion of 7 up to 20 cigarettes our patient never showed any symptoms of a severe or life-threatening nicotine intoxication. In the last decades no lethal nicotine intoxication after ingestion of cigarettes in adults was published in the literature.
This does not prove that it is safe to eat cigarettes, but it does provide a clear counter example to the bold claim of "If a person ate one pack of cigarettes, he/she would die."
