Alosetron is primarily used in the treatment of severe irritable bowel syndrome (IBS) in women who have not responded adequately to conventional therapy. It is particularly effective for managing IBS with diarrhea as the predominant symptom. The drug works by blocking serotonin receptors in the gastrointestinal tract, which helps to slow down bowel movements, reduce abdominal pain, and alleviate discomfort associated with IBS. Due to its potential side effects, including severe constipation and ischemic colitis, it is prescribed under strict medical supervision and is typically reserved for cases where other treatments have failed. Patients are often required to enroll in a risk management program to ensure safe use.