The stomach is a sturdy pouch-like organ located in the upper abdomen below the lungs. The wall of this pouch is called the gastric wall and consists of three layers of tissue: the inner mucosal layer, the middle muscle layer, and the outer serosal layer. The mucosal layer contains gastric glands responsible for secreting mucus, gastric acid, and pepsin.

Gastric acid is highly acidic, typically with a pH around 3; when food enters the stomach, gastric acid secretion increases significantly, lowering the pH to below 2. Pepsin functions to digest and break down proteins. Mucus is a gel-like bicarbonate barrier that lubricates and isolates, separating the mucosal epithelium from gastric acid and pepsin, thereby protecting the mucosa from corrosion and digestion.

So, what exactly is the impact of drinking tea on the stomach?

First, drinking tea replenishes water. When the body is well-hydrated, the mucosa secretes sufficient mucus, ensuring better protection for the epithelial layer.

Second, the pH of tea typically ranges between 5.5 and 7, making it weakly acidic. Compared to the strong acidity of gastric acid, this is negligible and does not irritate the gastric mucosa or neutralize gastric acid.

Third, tea contains caffeine, which briefly stimulates the central nervous system, thereby promoting gastric juice secretion and gastrointestinal motility to aid digestion—hence the saying "tea aids digestion." However, if there is no food in the stomach, excess gastric acid may irritate the gastric mucosa, causing a burning or stinging discomfort. Therefore, it is advisable to avoid drinking tea on an empty stomach.

Lastly, it is important to note the significant impact of mental state on the stomach. The stomach is jointly innervated by the sympathetic and parasympathetic nervous systems. When the body is in a calm state, parasympathetic dominance facilitates the digestion and absorption of nutrients and energy replenishment. When the body is excited or in an adverse environment, sympathetic activity increases, mobilizing the body's potential and adaptive capacity to cope with drastic changes and maintain internal stability.

Thus, the coordination of neural activity—including lifestyle regularity, sleep adequacy, emotional fluctuations, and stress balance—plays a crucial role in stomach function and health. If drinking tea helps regulate emotions and relieve stress, it not only does not harm the stomach but instead serves as a beneficial aid for gastric health.