A dog can be administered an osmotic, stimulant, emollient, laxative or lubricant laxative. Milk is an osmotic laxative. Bisacodyl, also known as Dulcolax, is a typical stimulant laxative. Laxatives should only be used for constipation and no other digestive ailment.
Using milk as an osmotic laxative pulls fluid into the bowels by exceeding the amount of lactase that the dog’s intestines can absorb. The typical dosage for Dulcolax, the commonly used stimulant laxative, also optimizes intestinal movement, but can cause adverse effects for the colon. Emollient laxatives often contain docusates; these are inappropriate for a dog who is dehydrated. Mineral oil is a common lubricant laxative, but may cause vitamin deficiency if used regularly.