According to MedicineNet, stool softeners provide preventative care for constipation and their design is not to treat it, while stimulant laxatives irritate the lining of the intestines and force stool through the body. Drinking lots of water while taking either a stool softener, or a stimulant or osmotic laxative is recommended, as it prevents dehydration and aids in the digestive process.
According to WebMD, osmotic laxatives, like Milk of Magnesia or Miralax, have the ability to "draw fluids into the intestine from other tissue;" this extra fluid makes it easier for the stool to pass. Emollient laxatives, or stool softeners, add moisture to the stool to prevent hardening of the feces without stimulating or increasing the number of bowel movements. Stimulant laxatives, including Ex-Lax, Correctol and Senokot, cause irritation of the intestinal lining to move stool through the body more quickly.
The Mayo Clinic reminds patients that "laxatives are to be used to provide short-term relief only." Making dietary changes is recommended to those experiencing constipation. Increasing roughage from whole grains, fruit, leafy vegetables and bran along with drinking six to eight full glasses of water and other liquids daily is known to improve bowel function. Cheese and highly refined carbohydrates, as those found in pastries, cakes and candy often make the condition worse. Before a doctor prescribes a laxative, the patient should inform him of any dietary restrictions as some laxatives are high in sodium or sugar.