This Amount Will Kill You (Water, Coffee, Salt, Apple Seeds and Can...

One definition of a the difference between a poison and a non-poison is the dose. Many benign substances can be deadly if too much is ingested.

The dose makes the poison (link.)

This post is going to explore the amounts of several substances that can kill you and why.

Water

So how much water does it take to kill you? Surprisingly little.

It only takes 6 litres to kill a 73 kg (165 lb) person if consumed over a short period of time. The condition is called hyponatremia.

Drinking too much water causes the fluid outside the cells to become dilute in electrolytes and cause that water to cross into the cells which are higher in concentration to balance things out.

The cells throughout your body will swell and in the brain this will cause headaches, confusion, drowsiness and changes in you personality. The cellular swelling may in some cases be so severe that it blocks the flow of blood to your brain.

All this interference to your brain and central nervous system could result in brain damage, seizures, coma and death.

Coffee

The MSDS sheet for caffeine tells me that the LD50 for rats is 192 mg/kg. If this translates over to humans then all its takes is 15.7 g of caffeine to kill an 82 kg (180 lb) person (well half of them).

The caffeine calculator tells me that this is about 75 cups of brewed coffee.

That's a lot of coffee and it would require extreme dedication to get that much into you by this route but it might not be so hard if your were popping caffeine pills to stay awake.

Caffeine is a neurotoxin created by plants to kill insects. Humans are more resistant to it than bugs (or maybe we just weigh more) so it only affects us by keeping us awake. The symptoms of too much caffeine or a bad reaction to caffeine are trouble breathing, hallucinations, vomiting, irregular or fast heartbeat and convulsions.

Salt

The MSDS sheet on salt indicates that 3 g per kg for rats will kill about one half of them (poor rats). Again, if this data carries over to humans then it would take about 250 g to kill an 82 kg (180 lb) person (again, half of them). That's about half a pound.

The cause of death will be hypernatremia. Too much salt in your system will cause the water in your cells to move out into the bloodstream. As the water leaves your brain it can shrink and bleed. You know where this is going, nowhere good (seizures, coma and death).

Basically it's not a good death.

Apple Seeds

Apple seeds contain cyanide and the MSDS sheet for cyanide(http://www.sciencelab.com/msds.php?msdsId=9927711) tells us that the LD50 is quite low, 6.44 mg/kg in you guessed it, rats.

The CDC data is even lower and it says that 1 or 2 mg/kg will kill a human.

If you weighed 82 kg (180 lbs) this translates to 0.082 grams and 0.164 grams.

An apple seed contains about 0.5 mg of cyanogenic compounds so you will need to eat AND FINELY MASTICATE about 150 to 300 apple seeds to kill you.

Apple seeds are tough little structures and unlikely to break down before they, ahem, pass out of your system. So don't worry too hard about eating apple seed or two.

Cannabis

Marijuana is not that lethal. Some say that it is not lethal at all and with good cause.

It is estimated that you would have to smoke 680 kg of weed in 15 minutes (source) to kill you.

This is probably why no stoners have ever died from cannabis alone.

This Amount Will Kill You (Water, Coffee, Salt, Apple Seeds and Cannabis)

Water

Coffee

Salt

Apple Seeds

Cannabis

Water Toxicity References

Caffeine Toxicity References

Salt Toxicity References

Apple Seed Toxicity References

Cannabis Toxicity Reference