http://emedicine.medscape.com/article/187249-overview Medscape Article Lactose intolerance~overview Lactose intolerance~overview EMedicine Primary lactose intolerance Lactose intolerance~overview «Lactose Intolerance» short explanation «Lactose Intolerance» Primary lactose intolerance Lactose intolerance~overview http://emedicine.medscape.com/article/187249-overview