Odynophagy is pain on swallowing, felt as food or liquid travels from the mouth through the oesophagus to the stomach. It differs from dysphagia, which is difficulty swallowing: odynophagy is specifically about pain. Common causes include oesophagitis from acid reflux, infections such as Candida or herpes simplex in immunocompromised patients, pill-induced injury, and corrosive ingestion. In nutrition and dietetic practice, odynophagy is a red flag for inadequate intake, since patients instinctively avoid eating and can lose weight rapidly; management involves treating the underlying inflammation, modifying food textures toward soft, moist, non-acidic options, and considering nutritional support if intake remains poor. Persistent odynophagy with weight loss warrants urgent investigation to exclude malignancy.