Does plain milk nourish or irritate the stomach?
Under normal circumstances, pure milk can be beneficial for the stomach when gastric conditions are good. However, when there is excessive gastric acid secretion, pure milk may irritate the stomach. The detailed analysis is as follows:

If gastric health is good, drinking pure milk can help nourish the stomach. Pure milk can to some extent protect the gastric mucosa and reduce direct irritation of the stomach lining by gastric acid, thus contributing to stomach health. At the same time, pure milk has a neutralizing effect on gastric acid, helping to relieve discomfort caused by excess stomach acid.
However, for individuals with excessive gastric acid secretion—such as those suffering from gastric ulcers, gastroesophageal reflux disease (GERD), or gastritis—the protein and calcium in pure milk may stimulate increased gastric acid production, thereby worsening gastric discomfort and leading to symptoms such as bloating, stomach pain, and loss of appetite.
Since pure milk contains significant amounts of protein and lactose, excessive consumption may lead to indigestion, resulting in symptoms like abdominal bloating, abdominal pain, and diarrhea. Therefore, pure milk should be consumed in moderation. When drinking milk, it is advisable to choose warm milk and avoid consuming it too cold to minimize irritation to the gastric mucosa.