This is a pilot clinical investigation. Patients who meet the eligibility criteria and provide signed informed consent will be randomized to receive either an active product (Uracyst®) or placebo intravesically via a bladder catheter weekly for 6 weeks, followed by 6 weeks of follow-up period.

Inclusion Criteria:

• Are female of male patient 18 years or older
• Have been previously diagnosed with IC/PBS.
• Are willing to provide informed consent
• Available for the duration of the study including treatment and follow-up (12 weeks)

Exclusion Criteria:

• Pregnant or lactating female.
• Are currently or have previously received investigational drugs within thirty (30) days of screening.
• Previous therapy for IC/PBS
• Have any medical condition/disease that could interfere with patient compliance or interfere with interpretation of the study results.
• Are unable or unwilling to comply with protocol requirements
• Are unable to read, understand, and provide written informed consent.