Urovex Butterbur Extract 60 SoftgelsDietary Supplement Supports Healthy Bladder Function Urovex Butterbur Extract supports healthy bladder function. This patented, standardized extract contains the biologically active components petasin and isopetasin and is specially processed to remove undesirable pyrrolizidine alkaloids. Urovex Butterbur Extract may also be used for other traditional applications.