This paper has been generated to provide information on the effectiveness of capsaicin treatment among patients with overactive or hypersensitive bladder. The evaluation process required approximately 14 (overactive bladder) and 11 (hypersensitive bladder and primary detrusor instability) participants who received capsaicin intravesically. The solution consisted of capsaicin (concentration = 1 mM/L) diluted in 30 per cent ethanol solution 100 ml. All participants went through at least 1 urodynamic test 1 month before and after receiving capsaicin intravesical instillation. The capsaicin treatment for overactive and hypersensitive bladders was very effective. On the average, (overactive bladder) participants' voiding needs decreased from 16.5 +/- 4.8 times/day to 8.6 +/- 2.5 times/day, leakage from 9.7 +/- 8.1 times/day to 2.4 +/- 4.3 times/day, bladder capacity from 160.1 +/- 123.3 ml to 236.9 +/- 146.1 ml, and detrusor contraction from 71.1 +/- 29.2 cm/H2O to 57.3 +/- 27.2 cm/H2O. On average, (hypersensitive bladder and primary detrusor instability) participants' voiding needs decreased from (Day time) 19.45 +/- 17.99 times to 12.00 +/- 8.91 times/day, (Night time) 7.09 +/- 6.03 times to 4.09 +/- 3.8 times, bladder capacity from 197.40 +/- 156.06 ml to 323.45 +/- 129.46 ml, and detrusor contraction from 32.64 +/- 22.77 cm/H2O to 36.64 +/- 19.22 cm/H2O. Capsaicin efficiency was rated very high for both overactive and hypersensitive bladder and primary detrusor instability. In Thailand, it has been possible to produce capsaicin using local chili supplies, thus the price of the drug itself is very economical. When considering the efficiency and the inexpensive cost of capsaicin, this treatment would be another great alternative for overactive and hypersensitive bladder cure.