'Gastro-esophageal reflux' is the passage of gastric content into the esophagus. Resulting typical symptoms are denoted as 'reflux like dyspepsia'. 'Reflux esophagitis' is the endoscopic or microscopic evidence of damage to the esophageal mucosa. Long-term intraesophageal pH-monitoring will establish 'pathologic gastroesophageal reflux' when 'acid exposure' time exceeds 5% of the monitoring time. GERD, 'gastro-esophageal reflux disease', is present when symptoms and/or esophagitis are caused by reflux. 'Columnar lined esophagus' is a better expression than 'Barret's esophagus'. Esophageal acid exposure increases during the day with a peak in the evening and little reflux after midnight. Treatment should probably be concentrated to evening time and not so much to night time.