Well, in our gut we basically have many, many bacterial cells. In fact, we have ten times as many bacterial cells as the cells inside our body. We have over 100 trillion bacterial cells inside our body, inside our gut, and this is about £3 of bacterial cells. Now, these cells, just like any other cells in nature, actually need ATP molecules to survive. And these cells use lactic acid fermentation, and when there is a build up of lactose inside our colon, these cells will use the lactose, the bacterial cells will use the lactose and break that lactose down to form ATP molecules in the process that will form lactate. So lactic acid, and if there's a build up of lactic acid lactate in our colon, that will cause the water to move out of the cell and into that lumen of the colon and that will lead to water restores.