Methanol poisoning is the toxic reaction to the ingestion or absorption of methanol - a form of alcohol made from wood instead of starches. Like regular alcohol, methanol can depress the central nervous system resulting in the slowing of the heart and breathing. In addition, when the liver metabolizes methanol, it creates formic acid, a chemical which interferes with the capacity of the mitochondria to use oxygen. This results in hypoxia and death of the affected tissues.
The optic nerve is particularly sensitive to the effect of methanol and even a non-fatal dose can destroy the nerve, leading to permanent blindness. In cases of fatalities, death is usually by respiratory arrest.
Unfortunately, methanol poisoning presents with many of the same symptoms of alcohol use. In addition, methanol's effects often do not become apparent for at least ten hours after ingestion (where alcohol's effect is more or less immediate and its metabolism by the body is much faster).
Ironically, as Gregory House so ably demonstrated on Clarence, ethanol prevents the conversion of methanol to formic acid by the liver by competitive inhibition. In such cases, instead of being processed by the liver, the methanol is processed by the kidneys and disposed of in the urine. The use of sodium bicarbonate is also common as methanol can lead to acidosis. Dialysis can also be used to remove both the methanol and formic acid.
Methanol is much more toxic than alcohol. A dose as low as 30ml can be fatal, although generally the fatal dose is between 100 and 125 ml. As little as 10ml can cause blindness.