Does a stroke only paralyze the right side?

If on left brain: Strokes secondary to emboli from a distance, most commonly wind up on left side of brain affecting right arm and leg, but one can have weakness on the left due to a stroke on the right side. Blockage of large, medium, and small vessels can occur in various parts of the brain, and often the brainstem.

Depends : On where the stroke occurs in the brain. The paralysis is usually on the opposide side of the stroke in the brain, so a left sided stroke would cause right paralysis.