It is variable. About 60–240 ml is fatal. But, even 30–60 ml have proved fatal and recovery has occurred after absorption of 500–600 ml of absolute methanol.

The smallest amount reported to cause death is 15 ml of 40% methanol and 4 ml is the lowest recorded toxic dose.

Fatal period
Usually 24–36 hours. But, may be delayed for 3–4 days.

Signs and Symptoms of Methanol Consumption
Signs and symptoms vary according to

• Amount Ingested,
• Presence of Folate Difienciency
• Whether or not there was simultaneous ethanol consumption.

Onset of symptoms is prolonged – as long as 24-36 hours – when sufficient toxic metabolites have accumulated

• Dizziness
• Vertigo
• Nausea
• Vomiting
• Severe abdominal pain or cramps in epigastric region due to pancreatic necrosis
• Muscular weakness
• Dyspnea
• Cyanosis
• Effect on CNS is more intense and persistent than ethanol
• Visual disturbances – they vary from photophobia, blurred vision, concentric diminution of visual field for color to be followed by partial blindness. But, these visual changes are not uniformly noted. Cloudy, blurred, misty or indistinct vision (described as similar to ‘stepping out in to a show field’) is typical.