Abstract Purpose Present therapeutic approaches to control bladder pain are clinically and scientifically unsatisfactory, and pain in the lower urinary tract remains a challenge even to the skilled urologist. A randomized placebo controlled study was done to evaluate intravesical capsaicin for severe bladder pain. Followup was 6 months. Materials and Methods A total of 36 patients was prospectively randomized into those receiving 10 micromolar intravesical capsaicin twice weekly for 1 month (group 1) or placebo (group 2). All patients had pelvic pain for at least 6 months, and had no urinary tract infection within the last 3 months, functional disorders of the lower urinary tract, or other vesical or urethral pathology. Pretreatment voiding pattern and pain score were recorded. Patients were evaluated immediately at the end of treatment (primary end point) and 6 months later (secondary end point). Results Both groups were adequately homogenous with regard to age, sex ratio, duration of disease, voiding pattern and pain score. At both end points group 1 had significant improvement in frequency and nocturia but no improvement in urgency. No change was noted in group 2. A significant decrease in pain score was found in group 1 at the primary (mean plus or minus standard deviation 3.22 plus/minus 0.42, p less than 0.01) and secondary (3.83 plus/minus 0.47, p less than 0.01) end points compared to before treatment (5.61 plus/minus 0.40, chi-square with 2 degrees of freedom 29.25, p less than 0.0001). A significant improvement was also observed in the placebo group, in which the pretreatment pain score (5.47 plus/minus 0.37) was decreased at the primary (4.47 plus/minus 0.36, p less than 0.01) and secondary (4.48 plus/minus 0.34, p less than 0.01, chi-square with 2 degrees of freedom 12.71, p less than 0.002) end points. There were no statistically significant differences between the 2 groups. Conclusions We confirmed the beneficial effect of intravesical instillation of capsaicin on voiding pattern in patients with hypersensitive disorders (frequency and nocturia). We could not confirm improvement in pain score after capsaicin treatment compared to placebo. Possibly a larger dose of capsaicin would be more effective in controlling pain and neurological disease of the bladder.