Many cathartics are available with different mechanisms of action. Saline cathartics e.g. magnesium hydroxide and magnesium sulphate pro-duce a watery evacuation in 1-3 hours. Stimulant cathartics e.g. senna, bisacodyl and agarol produce a soft to semi-fluid stool in 6 - 8 hours. Bulk-formers e.g. Isphagula Husk and Sterculia produce a softening of the stool in 1-3 days. Lubricant cathartics e.g. mineral oil softens the stool in 6-8 hours.
