| Header | Description |
| K00* | Disorders of tooth development and eruption |
| K01* | Embedded and impacted teeth |
| K02* | Dental caries |
| K02.5* | Dental caries on pit and fissure surface |
| K02.6* | Dental caries on smooth surface |
| K03* | Other diseases of hard tissues of teeth |
| K03.8* | Other specified diseases of hard tissues of teeth |
| K04* | Diseases of pulp and periapical tissues |
| K04.0* | Pulpitis |
| K04.9* | Other and unspecified diseases of pulp and periapical tissues |
| K05* | Gingivitis and periodontal diseases |
| K05.0* | Acute gingivitis |
| K05.1* | Chronic gingivitis |
| K05.2* | Aggressive periodontitis |
| K05.21* | Aggressive periodontitis, localized |
| K05.22* | Aggressive periodontitis, generalized |
| K05.3* | Chronic periodontitis |
| K05.31* | Chronic periodontitis, localized |
| K05.32* | Chronic periodontitis, generalized |
| K06* | Other disorders of gingiva and edentulous alveolar ridge |
| K06.0* | Gingival recession |
| K06.01* | Gingival recession, localized |
| K06.02* | Gingival recession, generalized |
| K08* | Other disorders of teeth and supporting structures |
| K08.1* | Complete loss of teeth |
| K08.10* | Complete loss of teeth, unspecified cause |
| K08.11* | Complete loss of teeth due to trauma |
| K08.12* | Complete loss of teeth due to periodontal diseases |
| K08.13* | Complete loss of teeth due to caries |
| K08.19* | Complete loss of teeth due to other specified cause |
| K08.2* | Atrophy of edentulous alveolar ridge |
| K08.4* | Partial loss of teeth |
| K08.40* | Partial loss of teeth, unspecified cause |
| K08.41* | Partial loss of teeth due to trauma |
| K08.42* | Partial loss of teeth due to periodontal diseases |
| K08.43* | Partial loss of teeth due to caries |
| K08.49* | Partial loss of teeth due to other specified cause |
| K08.5* | Unsatisfactory restoration of tooth |
| K08.53* | Fractured dental restorative material |
| K08.8* | Other specified disorders of teeth and supporting structures |
| K09* | Cysts of oral region, not elsewhere classified |
| K11* | Diseases of salivary glands |
| K11.2* | Sialoadenitis |
| K12* | Stomatitis and related lesions |
| K12.3* | Oral mucositis (ulcerative) |
| K13* | Other diseases of lip and oral mucosa |
| K13.2* | Leukoplakia and other disturbances of oral epithelium, including tongue |
| K13.7* | Other and unspecified lesions of oral mucosa |
| K14* | Diseases of tongue |
| K20* | Esophagitis |
| K21* | Gastro-esophageal reflux disease |
| K22* | Other diseases of esophagus |
| K22.1* | Ulcer of esophagus |
| K22.7* | Barrett's esophagus |
| K22.71* | Barrett's esophagus with dysplasia |
| K25* | Gastric ulcer |
| K26* | Duodenal ulcer |
| K27* | Peptic ulcer, site unspecified |
| K28* | Gastrojejunal ulcer |
| K29* | Gastritis and duodenitis |
| K29.0* | Acute gastritis |
| K29.2* | Alcoholic gastritis |
| K29.3* | Chronic superficial gastritis |
| K29.4* | Chronic atrophic gastritis |
| K29.5* | Unspecified chronic gastritis |
| K29.6* | Other gastritis |
| K29.7* | Gastritis, unspecified |
| K29.8* | Duodenitis |
| K29.9* | Gastroduodenitis, unspecified |
| K31* | Other diseases of stomach and duodenum |
| K31.8* | Other specified diseases of stomach and duodenum |
| K31.81* | Angiodysplasia of stomach and duodenum |
| K35* | Acute appendicitis |
| K35.2* | Acute appendicitis with generalized peritonitis |
| K35.3* | Acute appendicitis with localized peritonitis |
| K35.8* | Other and unspecified acute appendicitis |
| K35.89* | Other acute appendicitis |
| K38* | Other diseases of appendix |
| K40* | Inguinal hernia |
| K40.0* | Bilateral inguinal hernia, with obstruction, without gangrene |
| K40.1* | Bilateral inguinal hernia, with gangrene |
| K40.2* | Bilateral inguinal hernia, without obstruction or gangrene |
| K40.3* | Unilateral inguinal hernia, with obstruction, without gangrene |
| K40.4* | Unilateral inguinal hernia, with gangrene |
| K40.9* | Unilateral inguinal hernia, without obstruction or gangrene |
| K41* | Femoral hernia |
| K41.0* | Bilateral femoral hernia, with obstruction, without gangrene |
| K41.1* | Bilateral femoral hernia, with gangrene |
| K41.2* | Bilateral femoral hernia, without obstruction or gangrene |
| K41.3* | Unilateral femoral hernia, with obstruction, without gangrene |
| K41.4* | Unilateral femoral hernia, with gangrene |
| K41.9* | Unilateral femoral hernia, without obstruction or gangrene |
| K42* | Umbilical hernia |
| K43* | Ventral hernia |
| K44* | Diaphragmatic hernia |
| K45* | Other abdominal hernia |
| K46* | Unspecified abdominal hernia |
| K50* | Crohn's disease [regional enteritis] |
| K50.0* | Crohn's disease of small intestine |
| K50.01* | Crohn's disease of small intestine with complications |
| K50.1* | Crohn's disease of large intestine |
| K50.11* | Crohn's disease of large intestine with complications |
| K50.8* | Crohn's disease of both small and large intestine |
| K50.81* | Crohn's disease of both small and large intestine with complications |
| K50.9* | Crohn's disease, unspecified |
| K50.91* | Crohn's disease, unspecified, with complications |
| K51* | Ulcerative colitis |
| K51.0* | Ulcerative (chronic) pancolitis |
| K51.01* | Ulcerative (chronic) pancolitis with complications |
| K51.2* | Ulcerative (chronic) proctitis |
| K51.21* | Ulcerative (chronic) proctitis with complications |
| K51.3* | Ulcerative (chronic) rectosigmoiditis |
| K51.31* | Ulcerative (chronic) rectosigmoiditis with complications |
| K51.4* | Inflammatory polyps of colon |
| K51.41* | Inflammatory polyps of colon with complications |
| K51.5* | Left sided colitis |
| K51.51* | Left sided colitis with complications |
| K51.8* | Other ulcerative colitis |
| K51.81* | Other ulcerative colitis with complications |
| K51.9* | Ulcerative colitis, unspecified |
| K51.91* | Ulcerative colitis, unspecified, with complications |
| K52* | Other and unspecified noninfective gastroenteritis and colitis |
| K52.2* | Allergic and dietetic gastroenteritis and colitis |
| K52.8* | Other specified noninfective gastroenteritis and colitis |
| K52.83* | Microscopic colitis |
| K55* | Vascular disorders of intestine |
| K55.0* | Acute vascular disorders of intestine |
| K55.01* | Acute (reversible) ischemia of small intestine |
| K55.02* | Acute infarction of small intestine |
| K55.03* | Acute (reversible) ischemia of large intestine |
| K55.04* | Acute infarction of large intestine |
| K55.05* | Acute (reversible) ischemia of intestine, part unspecified |
| K55.06* | Acute infarction of intestine, part unspecified |
| K55.2* | Angiodysplasia of colon |
| K55.3* | Necrotizing enterocolitis |
| K56* | Paralytic ileus and intestinal obstruction without hernia |
| K56.4* | Other impaction of intestine |
| K56.5* | Intestinal adhesions [bands] with obstruction (postinfection) |
| K56.6* | Other and unspecified intestinal obstruction |
| K56.60* | Unspecified intestinal obstruction |
| K56.69* | Other intestinal obstruction |
| K57* | Diverticular disease of intestine |
| K57.0* | Diverticulitis of small intestine with perforation and abscess |
| K57.1* | Diverticular disease of small intestine without perforation or abscess |
| K57.2* | Diverticulitis of large intestine with perforation and abscess |
| K57.3* | Diverticular disease of large intestine without perforation or abscess |
| K57.4* | Diverticulitis of both small and large intestine with perforation and abscess |
| K57.5* | Diverticular disease of both small and large intestine without perforation or abscess |
| K57.8* | Diverticulitis of intestine, part unspecified, with perforation and abscess |
| K57.9* | Diverticular disease of intestine, part unspecified, without perforation or abscess |
| K58* | Irritable bowel syndrome |
| K59* | Other functional intestinal disorders |
| K59.0* | Constipation |
| K59.3* | Megacolon, not elsewhere classified |
| K60* | Fissure and fistula of anal and rectal regions |
| K61* | Abscess of anal and rectal regions |
| K61.3* | Ischiorectal abscess |
| K62* | Other diseases of anus and rectum |
| K62.8* | Other specified diseases of anus and rectum |
| K63* | Other diseases of intestine |
| K63.8* | Other specified diseases of intestine |
| K64* | Hemorrhoids and perianal venous thrombosis |
| K65* | Peritonitis |
| K66* | Other disorders of peritoneum |
| K68* | Disorders of retroperitoneum |
| K68.1* | Retroperitoneal abscess |
| K70* | Alcoholic liver disease |
| K70.1* | Alcoholic hepatitis |
| K70.3* | Alcoholic cirrhosis of liver |
| K70.4* | Alcoholic hepatic failure |
| K71* | Toxic liver disease |
| K71.1* | Toxic liver disease with hepatic necrosis |
| K71.5* | Toxic liver disease with chronic active hepatitis |
| K72* | Hepatic failure, not elsewhere classified |
| K72.0* | Acute and subacute hepatic failure |
| K72.1* | Chronic hepatic failure |
| K72.9* | Hepatic failure, unspecified |
| K73* | Chronic hepatitis, not elsewhere classified |
| K74* | Fibrosis and cirrhosis of liver |
| K74.6* | Other and unspecified cirrhosis of liver |
| K75* | Other inflammatory liver diseases |
| K75.8* | Other specified inflammatory liver diseases |
| K76* | Other diseases of liver |
| K76.8* | Other specified diseases of liver |
| K80* | Cholelithiasis |
| K80.0* | Calculus of gallbladder with acute cholecystitis |
| K80.1* | Calculus of gallbladder with other cholecystitis |
| K80.2* | Calculus of gallbladder without cholecystitis |
| K80.3* | Calculus of bile duct with cholangitis |
| K80.4* | Calculus of bile duct with cholecystitis |
| K80.5* | Calculus of bile duct without cholangitis or cholecystitis |
| K80.6* | Calculus of gallbladder and bile duct with cholecystitis |
| K80.7* | Calculus of gallbladder and bile duct without cholecystitis |
| K80.8* | Other cholelithiasis |
| K81* | Cholecystitis |
| K82* | Other diseases of gallbladder |
| K82.A* | Disorders of gallbladder in diseases classified elsewhere |
| K83* | Other diseases of biliary tract |
| K83.0* | Cholangitis |
| K85* | Acute pancreatitis |
| K85.0* | Idiopathic acute pancreatitis |
| K85.1* | Biliary acute pancreatitis |
| K85.2* | Alcohol induced acute pancreatitis |
| K85.3* | Drug induced acute pancreatitis |
| K85.8* | Other acute pancreatitis |
| K85.9* | Acute pancreatitis, unspecified |
| K86* | Other diseases of pancreas |
| K86.8* | Other specified diseases of pancreas |
| K90* | Intestinal malabsorption |
| K90.4* | Other malabsorption due to intolerance |
| K90.8* | Other intestinal malabsorption |
| K91* | Intraoperative and postprocedural complications and disorders of digestive system, not elsewhere classified |
| K91.3* | Postprocedural intestinal obstruction |
| K91.6* | Intraoperative hemorrhage and hematoma of a digestive system organ or structure complicating a procedure |
| K91.7* | Accidental puncture and laceration of a digestive system organ or structure during a procedure |
| K91.8* | Other intraoperative and postprocedural complications and disorders of digestive system |
| K91.84* | Postprocedural hemorrhage of a digestive system organ or structure following a procedure |
| K91.85* | Complications of intestinal pouch |
| K91.87* | Postprocedural hematoma and seroma of a digestive system organ or structure following a procedure |
| K92* | Other diseases of digestive system |
| K92.8* | Other specified diseases of the digestive system |
| K94* | Complications of artificial openings of the digestive system |
| K94.0* | Colostomy complications |
| K94.1* | Enterostomy complications |
| K94.2* | Gastrostomy complications |
| K94.3* | Esophagostomy complications |
| K95* | Complications of bariatric procedures |
