gastroenterology
Medical specialty dealing with the digestive system. Cross-referenced with 胃腸病学 (いちょうびょうがく), a near-synonym also meaning gastroenterology.
See also: 胃腸病学
He is a doctor specializing in gastroenterology.
I am reading a textbook on gastroenterology.
Also means gastroenterology; 消化器学 is a more common term in modern medical contexts.
Compound of 消化器 (しょうかき, 'digestive organs') + 学 (がく, 'study'). The derivation is straightforward from the kanji components.