The first two doses of magnesium sulfate cause the gallbladder to contract full providing the strength of the solution is sufficient. This has been establish by experimentation while monitoring the gallbladder with ultrasound. The stated solution strength of 1 tablespoon per 6 fluid ounces is adequate for this purpose. If it is reduce so is the effect.

The second two doses are to purge the intestines and to stop bile from being reabsorbed. These can certainly be reduced to help reduce the time one has to close to the toilet. I firstly reduced the dose of these two solution by a third to 1 desert-spoon (equal to 2 teaspoons). Then I stop taking the 4th dose altogether and kept the 3rd to 1 desert-spoon full. I would make sure I woke up early around 6 am to take the 3rd solution and this meant that I had finished with the diarrhoea by lunch time.