Abstract: The present invention provides methods, compositions, and kits for treating bladder disorders or conditions, in which botulinum toxin is topically administered to the mucosal inner lining or urothelium of the bladder, of a subject in need thereof, for transmucosal delivery across the urothelium to surrounding bladder wall musculature and/or neuronal tissue. Rather than requiring injection, the toxin instead may be administered by instillation in solution via the urethra. In particular, the botulinum toxin is administered in conjunction with a positively charged or lipophilic carrier comprising a positively charged polymeric backbone or a hydrophobic backbone with covalently attached groups that enhance transmucosal transport across the urothelium and may also stabilize the botulinum toxin in aqueous formulations.