Constipation is a common problem. It means either going to the toilet less often than usual to empty the bowels, or passing hard or painful stools (faeces). Constipation may be caused by not eating enough fibre, or not drinking enough fluids. It can also be a side-effect of certain medicines, or related to an underlying medical condition. In many cases, the cause is not clear. Laxatives are a group of medicines that can treat constipation. Ideally, laxatives should only be used for short periods of time until symptoms ease. Note: there is a separate leaflet on constipation in children.