Why do your eyes shake when on ecstasy?

Answer 1

While under the influence: sometimes as it can be laced with amphetamines or caffeine. Not usually afterwards though.

If the only active ingredient in the ecstasy pill is MDMA, your hands shouldn't be much shakier than normal.

Answer 2

Your eyes shaking is called Nysagmus. The ecstasy is affecting parts of your nervous system, causing your eyes to shake and see blurred and double vision.