I had a spate of gallbladder attacks last year.
Reduced fat in diet, refrained from large amounts of fat at one sitting, lost weight - no more gallbladder attacks.
I wanted to avoid having my gallbladder removed, because it does serve some purpose. Body uses bile to digest fat. Gallbaldder stores bile and releases through bile duct into intestines when body senses large amount of fat has been consumed. In caveman days we went without fat for days/weeks, then we killed a large animal amd consumed lots of fat at one sitting. Need for bile was thus highly variable, and gallbladder provides the burst of bile when we need it. When the gallbladder is removed, digestive tract gets a constant drip of bile, whether needed or not. Okay in most cases, because our fat intake is less variable than before. But some people experience less graceful handling of certain foods. Not a big downside, but some downside nonetheless.
The gallstone flushes are controversial - my reading indicates what are "flushed" are not gallstones, but rather oil/fat lumps from the oil ingested. You can retrieve some from your poop and cut into them, if they are soft and dissolve, they are not gallstones. (edit - see here
http://www.quackwatch.org/01QuackeryRelatedTopics/flushes.html )
The bile duct from gallbladder is very narrow (I looked up the diameter once, it is several mm I think - edit: 5-10mm) and if a slew of gallstones actually got flushed from gallbladder into the duct,, you'd feel massive pain and/or bile duct blockage which can be very serious indeed.
Ultrasound can identify and measure your gallstones. My largest one is 2.4 cm diameter, so I know it is not going through the bile duct no matter how many gallons of olive oil I consume.
Not a doctor at all, merely self-read in this area, so take the above w/ a grain of salt.