The solutions (including concentrates, stock solutions and supersaturated solutions) described herein preferably consist essentially of calcium ions, orthophosphate ions, sodium ions, chioride ions and, optionally, fluoride ions and/or zinc ions in the concentrations already specified, and, if desired, colouring(s), flavouring(s) and/or preservative(s). More preferably, the solutions are substantially free from any ion or other ingredient which is not normally present in saliva.