Except from online encyclopaedia:
Ingesting as little as 10 mL (0.34 US fl oz) of pure methanol can cause permanent blindness by destruction of the optic nerve. 30 mL (1.0 US fl oz) is potentially fatal.[27] The median lethal dose is 100 mL (3.4 US fl oz), i.e., 1–2 mL/kg body weight of pure methanol.[28] The reference dose for methanol is 0.5 mg/kg in a day.[29][30] Toxic effects begin hours after ingestion, and antidotes can often prevent permanent damage.[27] Because of its similarities in both appearance and odor to ethanol (the alcohol in beverages), it is difficult to differentiate between the two; such is also the case with denatured alcohol, adulterated liquors or very low quality alcoholic beverages.
Methanol is toxic by two mechanisms. First, methanol can be fatal due to effects on the central nervous system, acting as a central nervous system depressant in the same manner as ethanol poisoning. Second, in a process of toxication, it is metabolised to formic acid (which is present as the formate ion) via formaldehyde in a process initiated by the enzyme alcohol dehydrogenase in the liver.[31] Methanol is converted to formaldehyde via alcohol dehydrogenase (ADH) and formaldehyde is converted to formic acid (formate) via aldehyde dehydrogenase (ALDH). The conversion to formate via ALDH proceeds completely, with no detectable formaldehyde remaining.[32] Formate is toxic because it inhibits mitochondrial cytochrome c oxidase, causing hypoxia at the cellular level, and metabolic acidosis, among a variety of other metabolic disturbances.[33]
