Methanol can be found in wood alcohol, or home-brewed alcohol. Methanol is converted to formaldehyde by alcohol dehydrogenase. Formaldehyde in turn is converted to formic acid, which is a toxic metabolite. In patients with methanol poisoning, the accumulation of methanol leads to an excess production of formic acid, which then leads to an anion gap metabolic acidosis. Accumulation of formic acid can cause central nervous system depression, vomiting and abdominal pain, and optic nerve obstruction leading to blindness. The treatment of choice for methanol poisoning is fomepizole or ethanol.