Intestinal gas-not a very pleasant thought! Gas can be a big problem for those who lack the enzymes to digest certain foods. Do products that advertise to eliminate this problem really work? This demonstration kit shows an over-the-counter enzyme Lactaid™ (lactase) in action! Flasks containing various sugar combinations with and without Lactaid™ are compared for gas production by yeast cells. Balloons inflate very quickly when digestible sugars are available to the lactose intolerant yeast cells. Inflated and non-inflated balloons dramatically illustrate the concept and consequences for students.Enough materials are provided in this kit to perform the demonstration seven times.