The medicine was aperient.

Answer: Option D

Bitter : having a sharp, pungent taste or smell; not sweet.
Sweet : having the pleasant taste characteristic of sugar or honey; not salt, sour, or bitter.
Giddy : having a sensation of whirling and a tendency to fall or stagger; dizzy.
Laxative : (chiefly of a drug or medicine) tending to stimulate or facilitate evacuation of the bowels.
Aperient : (chiefly of a drug) used to relieve constipation.

Synonym of Aperient is Laxative