hyperchlorhydria

{{Short description|Condition in which stomach acid is higher than reference range}}

Hyperchlorhydria, sometimes called chlorhydria, sour stomach or acid stomach,{{cite web |title=Dorland's Illustrated Medical Dictionary |publisher=Elsevier |url=http://dorlands.com/ |accessdate=9 July 2018 |archive-date=11 January 2014 |archive-url=https://web.archive.org/web/20140111192614/http://dorlands.com/ |url-status=dead }}{{cite web|url=http://bioportal.bioontology.org/ontologies/MEDDRA?p=classes&conceptid=http%3A%2F%2Fpurl.bioontology.org%2Fontology%2FMEDDRA%2F10041373#details/|title=Medical Dictionary for Regulatory Activities - Sour stomach - Classes - NCBO BioPortal|website=Bioportal.bioontology.org|accessdate=9 July 2018|archive-date=9 July 2018|archive-url=https://web.archive.org/web/20180709215644/http://bioportal.bioontology.org/ontologies/MEDDRA?p=classes&conceptid=http%3A%2F%2Fpurl.bioontology.org%2Fontology%2FMEDDRA%2F10041373#details/|url-status=dead}} refers to the state in the stomach where gastric acid levels are higher than the reference range. The combining forms of the name (chlor- + hydr-), referring to chlorine and hydrogen, are the same as those in the name of hydrochloric acid, which is the active constituent of gastric acid.

In humans, the normal pH is around 1 to 3, which varies throughout the day. The highest basal secretion levels are in the late evening (around 12 A.M. to 3 A.M.). Hyperchlorhydria is usually defined as having a pH less than 2.

In Zollinger–Ellison syndrome gastrin levels are increased, leading to excess gastric acid production, which can cause gastric ulcers.{{cite web|url=https://www.mayoclinic.org/diseases-conditions/zollinger-ellison-syndrome/symptoms-causes/syc-20379042|title=Zollinger-Ellison syndrome|accessdate=10 January 2025}}

Hypercalcemia also increases gastrin and gastric acid and can cause ulcers.{{citation needed|date=January 2025}}