The goals of this trial are to determine the efficacy and safety of two treatments for women experiencing fecal incontinence. First, we aim to compare the use of loperamide to placebo and second, to compare the use of anal sphincter exercises with biofeedback to usual care. The primary outcome is the change from baseline in the St. Mark's (Vaizey) Score 24. weeks after treatment initiation. As a Pelvic Floor Disorders Network (PFDN) trial, subjects are enrolling from eight PFDN clinical centers across the United States. A centralized data coordinating center supervises data collection and analysis. These two first-line treatments for fecal incontinence are being investigated simultaneously using a two-by-two randomized factorial design: a medication intervention (loperamide versus placebo) and a pelvic floor strength and sensory training intervention (anal sphincter exercises with manometry-assisted biofeedback versus usual care using an educational pamphlet). Interventionists providing the anal sphincter exercise training with biofeedback have received standardized training and assessment. Symptom severity, diary, standardized anorectal manometry and health-related quality of life outcomes are assessed using validated instruments administered by researchers masked to randomized interventions. Cost effectiveness analyses will be performed using prospectively collected data on care costs and resource utilization. This article describes the rationale and design of this randomized trial, focusing on specific research concepts of interest to researchers in the field of female pelvic floor disorders and all other providers who care for patients with fecal incontinence.