Some believe Napoleon took to much poison because he thought himself as godly so he assumed he would need to take more but it ended up making himself so sick he vomited up the poison.
Some even think due to him being farsighted he was unable to properly read the poison thus taking either to much so he became sick or not enough OR that it was to old.
And new theories say that the tapestry of his room was made of a special shade of green that probably contained arsenic to prevent it from fading. It sounds like bs, but it's not.
I remember in the movie The Terminal, Tom Hanks' character suggested that because of his farsightedness, he couldn't read the label and grabbed the wrong bottle.
Some even think due to him being farsighted he was unable to properly read the poison thus taking either to much so he became sick or not enough OR that it was to old.