Medical Mysteries

I was popping my four-o-clock in the afternoon pill, when Epo-Na asked curiously: ‘what is that?
‘Rat-poison’, I said. ‘It is what makes rats go dead, but because I am bigger than a rat, I don’t go dead.’
‘Then what is the point of taking it?, she asked, a little puzzled.
‘It is so that I won’t go dead’, I said grumpily.
‘How can a thing make a rat go dead and the same thing prevent you from going dead’, she asked.
‘Got me there’, I shrugged, ‘it is called  “medical mysteries”.’
She walked away, shaking her head and muttering something about human strangeness.