Hello. Gas may be associated with alli - especially if you eat more fat. Actually, gas may occur anytime you change your diet or add a new medication. It could be caused by your diet - hopefully you have increased the fiber in your diet which could lead to gas. If you are having gas with oily spotting, that could be due to eating too much fat.
You can try an over-the-counter product like simethicone (as found in Gas-X) to help - it is OK to take on alli. Also, if you are eating high fiber foods like beans or cruciferous vegetables like broccoli and cauliflower, a product such as Beano may help prevent the gas from forming.
Hope this helps!
Best of health!
Maria Marzella Sulli, Pharm.D.