★★★★☆
While fresh, more recently formed gallstones are the pea-green characteristic of new bile and might be supposed to be related to the olive oil used in the flush, there are several types of stones obtained in a flush. Tan, granular stones are also observed, as are dark-colored "pigmented" stones (pigmented by bilirubin) as well as yellow, fatty chaff.
Further, the olive-oil-stone theory does not in any way explain the presence of bile-duct flukes unseated by the cleanse. These were identified as Opisthorchis sinensis -- apparently my sushi-eating years left some souvenirs behind.
You can "explain away" stones all you want, but it's pretty hard to make olive oil into flukes complete with visible proboscis.