If your gallbladder contains sand no larger than 3 mm, one of the useful methods is to drink about 2 liters of rainwater per day. One of the methods I use the most is to drink 1-2 liters of rainwater or distilled water a day.
In this case, gallstones and sand are slowly removed, and even if they fall into the bile ducts, they do not remain in the bile duct because of the small size of the stones and do not cause serious complications. This method is safe although it takes a long time. You can drink for 2-3 months depending on the size of the stone. It also cleanses kidney stones in parallel with gallstones.