Question

ethanol is the most common alcoholic beverage but methanol is extreme harmful to human explain

Answer 1

As has been answered, ethanol is also poison to the body. Ethanol is a central nervous system depressant where methanol can cause blindness, and kill you. Different shape molecules react with the body differently. That pretty much goes for methanol and the rest of the alcohols. That goes pretty much with literally anything. Too much water can kill you and it isn’t considered toxic.

I understand your question, as printed, my answer is meant to try and broaden your thoughts toward chemistry in general. You can ask that same question about any chemical, not just alcohols.