The most common risks of potential side effects from taking stool softeners are abdominal pain, cramping, diarrhea, gas, bloating, nausea, vomiting, irritation around the rectum, and irritation in the throat (with liquid and syrup forms).
Less common, but more serious, potential side effects include bleeding from the rectum, dizziness, fainting, palpitations, weakness, sweating, trouble breathing, and allergic reactions (such as a rash, itching, swelling, dizziness, and difficulty with breathing).
Prolonged use of stool softeners can cause you to become dependent on laxatives and interfere with the ability of your body to absorb nutrients from food. This may lead to disturbances of fluids and electrolytes and decreased amounts of vitamins and minerals in your body, as well as softening of the bones (osteomalacia).
Docusate stool softeners have been classified as pregnancy category C drugs by the United States Food and Drug Administration, which means that they may cause harm to a developing fetus if used during pregnancy. These medications should only be used if your doctor determines that the benefit to the mother is greater than the risk of birth defect to the child. It is not known whether stool softeners pose a risk to a nursing child if taken by a breast-feeding woman.