Xerostomia is the medical term for dry mouth — the subjective feeling of oral dryness caused by too little saliva, from the Greek xeros, dry, and stoma, mouth. Hundreds of medicines cause it — antidepressants, antihistamines, blood-pressure drugs among them — as do radiotherapy to the head and neck, Sjögren’s syndrome, and simply ageing. Beyond discomfort, saliva protects teeth and starts digestion, so chronic dry mouth raises the risk of tooth decay, gum disease, and difficulty swallowing and tasting. Management means treating the cause where possible, plus saliva substitutes, sugar-free gum to stimulate flow, meticulous oral hygiene, and constant sipping of water. It is common, under-recognised, and very treatable.