Minor side effects of docusate sodium 100 milligram use include diarrhea, throat pain, rectal irritation, bloating and stomach cramps, according to Drugs.com. Rectal bleeding and allergic reactions, such as itching, swelling, dizziness, nausea and breathing difficulty, are rare but require immediate medical attention, notes WebMD.
Docusate sodium is a stool softener that works by increasing water absorption and retention by the stool mass in the gut, says WebMD. Doctors commonly prescribe it for the treatment of incomplete or infrequent bowel movements as well as their prevention. Patients ingest the medication in the form of capsules, syrup, liquid or drops for no longer than a week. If all goes well, relief comes within three days.