The Food and Drug Administration announced today that regulators are assessing at least 32 reports of liver problems between 1999 and 2008 in patients taking the weight-loss drug orlistat, sold as a prescription drug Xenical and more recently, as an over-the-counter medication called Alli.
In addition to liver problems, this drug is associated with causing gallstones. There are a number of sites citing it (I cannot post links just yet) including WorstPills.org
I believe this was the cause of my gallstones following two months of taking Alli. Plus, and incidentally I have liver problems which were identified at that time although I cannot say when they started.