Docusate is a surface-wetting agent, more commonly known as a stool softener. If prescribed, it should always be combined with a stimulant like Senokot. Current published literature indicates that patients usually respond as well to sennosides alone as they do when sennosides are combined with docusate.
One of the few times when docusate may be used alone is when the patient has a partial bowel obstruction. The onset of action for docusate is 12―72 hours.
You should note, however, that docusate should never be used in combination with mineral oil.
Reference
Twycross R, Wilcock A, Dean M. Canadian Palliative Care Formulary, 1st Canadian ed. Nottingham, UK: Palliativedrugs.com; 2010.