- Gastromalacia 537.89
- Gastroparalysis 536.3
- Gastroparesis 536.3
- Gastropathy 537.9
- Gastroptosis 537.5
- Gastrorrhagia 578.0
- Gastrorrhea 536.8
- Gastroschisis (congenital) 756.73
- Gastrospasm (neurogenic) (reflex) 536.8
- Gastrostaxis 578.0
- Gastrostenosis 537.89
- Gastrostomy
- Gastrosuccorrhea (continuous) (intermittent) 536.8
- Gaucher's
- GAVE (gastric antral vascular ectasia) 537.82
- Gayet's disease (superior hemorrhagic polioencephalitis) 265.1
- Gayet-Wernicke's syndrome (superior hemorrhagic polioencephalitis) 265.1
- Gee (-Herter) (-Heubner) (-Thaysen) disease or syndrome (nontropical sprue) 579.0
- Gélineau's syndrome (see also Narcolepsy) 347.00
- Gemination, teeth 520.2
- Gemistocytoma (M9411/3)
- General, generalized - see condition