You need to read the study Dr. Kellon sent you again. There were 28 subjects in the study. 3 subjects reported taking medications concurrently.
One of the educational purposes of ECIR is to help lay persons read studies and have some understanding of what they are reading. Members can cite studies themselves and often Dr. Kellon or one of the mods with research backgrounds( yes we have them here) will explain if the study was conducted properly, what might be a problem with it, etc.
This four day study demonstrated that a certain species of dandelion extract produced an increase in urine output with one dose, a smaller output with the second, and no increase with the third.
Dawn Wagstaff and Tipperary
Saline, MI 2003