We attempted to clarify the preventive effects of cyclohexenonic long-chain fatty alcohol on detrusor overactivity induced by mild bladder neck obstruction. Bladder neck obstruction was created by partial ligation of the urethra. Female Sprague-Dawley rats were divided into three groups: those with bladder neck obstruction treated without long-chain fatty alcohol, those with bladder neck obstruction with long-chain fatty alcohol (8 mg/kg, i.p., every day) and the sham-operated control group (A, B, and C groups, respectively). Six weeks after the induction of bladder neck obstruction, voiding behavior was observed in the metabolic cage, and a cystometrogram was performed in the experimental animals. Furthermore, Hematoxylin and Eosin, Azan-Mallory, and Bodian stainings were performed in these bladders. Bladder weight, voiding behaviors and a cystometry indicated that rats in the A group showed detrusor overactivity, which was improved by treatment with long-chain fatty alcohol. The proportion of connective tissue and the density of bundles of neurofibers in the bladder of the A group was significantly less than that in the other bladders. Mild bladder neck obstruction induces detrusor overactivity, which is improved by treatment with long-chain fatty alcohol.