This document discusses the use of Bacillus Calmette-Guérin (BCG) for treating superficial transitional cell carcinoma (TCC). It provides details on BCG's mechanism of action, effectiveness in reducing recurrence rates, recommended treatment schedule, side effects, and alternatives for BCG failures. BCG is an effective intravesical therapy that decreases recurrence rates from 70% to 30% by stimulating an immune response. While toxicities can occur, long-term maintenance therapy over 1 year is required for optimal results. Further research is still needed to determine the ideal BCG treatment regimen.