內科常見門診疾病
內科學的方法是透過病史詢問或面談後，進行理學檢查，根據病史與檢查所見做實驗診斷與影像檢查，以期在眾多鑑別診斷中排除可能性較低者，獲得最有可能的診斷；獲得診斷後，內科的治療方法包含追蹤觀察、生活方式、藥物、介入性治療（如心導管、內視鏡）等，根據病人的狀況調整藥物之使用，防止並處理副作用及併發症。
內科學是臨床醫學的一個專科，幾乎是所有其他臨床醫學的基礎，亦有醫學之母之稱。內科學的內容包含了疾病的定義、病因、致病機轉、流行病學、自然史、症狀、徵候、實驗診斷、影像檢查、鑑別診斷、診斷、治療、預後。
內科常見門診疾病中英文對照表
| 英文疾病名稱 | 中文疾病名稱 |
| Abdominal pain | 腹痛 |
| Acne vulgaris | 痤瘡 |
| Acute appendicitis | 急性闌尾炎 |
| Acute bronchitis | 急性支氣管炎 |
| Acute confusional state | 急性譫妄 |
| Acute conjuntivitis | 急性結膜炎 |
| Acute gastroenteritis | 急性胃腸炎 |
| Acute glomerulonephritis | 急性腎絲球腎炎 |
| Acute myocardial infarction | 急性心肌梗塞 |
| Acute pancreatitis | 急性胰臟發炎 |
| Acute pyelonephritis | 急性腎盂腎炎 |
| Acute renal failure | 急性腎衰竭 |
| Acute sinusitis | 急性鼻竇炎 |
| Acute tonsillitis | 急性扁桃腺炎 |
| Acquired immunodeficiency syndrome (AIDS) | 後天免疫不全症候群 |
| Alcoholic drunkenness | 酒醉 |
| Alcoholic gastritis | 酒精性胃炎 |
| Alcoholic liver cirrhosis | 酒精性肝硬化 |
| Alcoholic liver damage | 酒精性肝損害 |
| Allergic rhinitis | 過敏性鼻炎 |
| Anemia | 貧血 |
| Anemia (acute blood loss) | 急性出血後貧血 |
| Anemia (folate deficiency) | 葉酸缺乏性貧血 |
| Anemia (iron deficiency) | 缺鐵性貧血 |
| Anemia (vitamin B12 deficiency) | 維生素Ｂ１２缺乏性貧血 |
| Angina pectoris | 心絞痛 |
| Ankylosing spondylitis | 僵直性脊椎炎 |
| Anorexia | 厭食 |
| Anxiety state | 焦慮狀態 |
| Anxiety (stress reaction) | 焦慮(壓力反應) |
| Arrhythmia | 心律不整 |
| Arthritis, post-traumatic | 創傷後關節炎 |
| Arthropathy | 關節病變 |
| Ascariasis | 蛔虫病 |
| Asthma | 氣喘 |
| Atherosclerosis | 動脈粥樣硬化 |
| Atopic dermatitis | 異位性皮膚炎 |
| Atrial fibrillation | 心房顫動 |
| Atrial flutter | 心房撲動 |
| Backache | 背痛 |
| Bed sore | 褥瘡 |
| Behcet's syndrome | 畢賽氏徵候群 |
| Benign paroxysmal positional vertigo | 良性陣發性位置性眩暈 |
| Benign prostate hypertrophy | 攝護腺（前列腺）肥大 |
| Benign breast tumor | 乳房良性腫廇 |
| Bronchiectasis | 支氣管擴張症 |
| Cancer of bone and cartilage | 骨骼及關節軟骨之惡性腫瘤 |
| Cancer of breast, female | 女性乳房惡性腫瘤 |
| Cancer of cervix | 子宮頸惡性腫瘤 |
| Cancer of colon | 結腸惡性腫瘤 |
| Cancer of esophagus | 食道惡性腫瘤 |
| Cancer of gastrointestinal and peritoneum | 消化道及腹膜之惡性腫瘤 |
| Cancer of lung | 支氣管及肺惡性腫瘤 |
| Cancer of mouth | 口部惡性腫瘤 |
| Cancer of ovary | 卵巢惡性腫瘤 |
| Cancer of pancreas | 胰臟惡性腫瘤 |
| Cancer of prostate | 攝護腺(前列腺)之惡性腫瘤 |
| Cancer of rectum | 直腸惡性腫瘤 |
| Cancer of stomach | 胃惡性腫瘤 |
| Cancer of thyroid gland | 甲狀腺惡性腫瘤 |
| Cancer of unknown primary | 原發部位未明之惡性腫瘤 |
| Candidiasis | 念珠菌病 |
| Candidiasis (oral thrush) | 口腔念珠菌病(鵝口瘡) |
| Carpal tunnel syndrome | 腕隧徵候群 |
| Cellulitis and abscess | 蜂窩組織炎及膿瘍 |
| Cerebral hemorrhage | 大腦出血 |
| Cerebral infarction | 腦梗塞 |
| Cerebrovascular accident | 腦血管意外 |
| Cerebrovascular accident, old | 陳舊性腦血管意外 |
| Cervicitis | 子宮頸炎 |
| Chest pain | 胸痛 |
| Chickenpox | 水痘 |
| Cholecystitis | 膽囊炎 |
| Chronic bronchitis | 慢性支氣管炎 |
| Chronic glomerulonephritis | 慢性腎絲球腎炎 |
| Chronic hepatitis | 慢性肝炎 |
| Chronic obstructive pulmonary disease (COPD) | 慢性阻塞性肺疾病 |
| Chronic renal failure (End stage renal disease) | 慢性腎衰竭 |
| Chronic rhinitis | 慢性鼻炎 |
| Chronic sinusitis | 慢性鼻竇炎 |
| Cluster headache | 叢集型偏頭痛 |
| Common cold | 感冒 |
| Congestive heart failure | 鬱血性心臟衰竭 |
| Constipation | 便秘 |
| Contact dermatitis | 接觸性皮膚 |
| Convulsion | 痙攣 |
| Coronary artery disease | 冠狀動脈疾病 |
| Cramp (limbs) | 痙攣(四肢) |
| Cushing's syndrome | 庫興氏徵候群 |
| Cystitis, acute | 急性膀胱炎 |
| Deep vein thrombosis | 深部靜脈栓塞 |
| Dementia, presenile | 早發性老年癡呆症 |
| Dementia, senile | 老年癡呆症 |
| Depressive disorder | 憂鬱症 |
| Dermatitis herpetiform | 疹狀皮膚炎 |
| Dermatomyositis | 肌皮炎 |
| Diabetes mellitus | 糖尿病 |
| Diabetes mellitus foot (gangrene) | 糖尿病足(壞疽) |
| Diabetes mellitus with nephropathy | 糖尿病併腎病變 |
| Diabetes mellitus with peripheral circulatory disorder | 糖尿病併有末稍血管循環病變 |
| Diabetes mellitus with polyneuropathy | 糖尿病併多發性神經病變 |
| Diabetes mellitus with retinopathy | 糖尿病併視網膜病變 |
| Diabetes mellitus with lower limb ulcer | 糖尿病伴有下肢潰瘍 |
| Diaper rash | 尿布疹 |
| Dizziness and giddiness | 眩暈 |
| Drug abuse | 藥物濫用 |
| Drug dependence | 藥癮 |
| Drug eruption | 藥疹 |
| Drug poisoning | 藥物中毒 |
| Drug psychosis | 藥物所致之精神異常 |
| Drug withdrawal syndrome | 藥物戒斷徵候群 |
| Duodenal ulcer | 十二指腸潰瘍 |
| Dysfunctional uterine bleeding (DUB) | 功能異常性子宮出血 |
| Dysmenorrhea | 痛經症 |
| Dyspnea | 呼吸困難 |
| Eczema | 濕疹 |
| Edema | 水腫 |
| Electrolyte / fluid disease | 電解質及體液失調症 |
| Elevation of ALT, AST, or LDH | 胺基交換 或乳酸脫氫 之非特定性上升 |
| Emphysema | 肺氣腫 |
| Epilepsy | 癲癇 |
| Erysipelas | 丹毒 |
| Erythema multiforme | 多形性紅斑 |
| Erythema nodosum | 結節性紅斑 |
| Esophageal varices | 食道靜脈曲張 |
| Facial palsy / Bell's palsy | 貝爾氏麻痺（顏面神經麻痺） |
| Fatty liver | 脂肪肝 |
| Fever of unknown origin | 不明熱 |
| Fibrositis / rheumatism | 纖維組織炎/風濕症 |
| Frozen shoulder | 冷凍肩 ( 五十肩 ) |
| Functional disorders of bladder | 膀胱功能障礙 |
| Functional gastrointestinal disorder | 腸胃功能性障礙 |
| Furuncle/carbuncle | 癰及癤 |
| Gait abnormality | 步態異常 |
| Gallstone | 膽囊結石 |
| Gangrene | 壞疽 |
| Gastric ulcer | 胃潰瘍 |
| Gastritis / gastroduodenitis | 胃炎及胃十二指腸炎 |
| Gastrointestinal bleeding | 胃腸道出血 |
| Gingival / periodontal disease | 齒齦與牙周疾病 |
| Goiter | 甲狀腺腫大 |
| Gonorrhea | 淋病 |
| Gouty arthritis | 痛風性關節炎 |
| Gouty nephropathy | 痛風性腎病變 |
| Headache | 頭痛 |
| Health checkup | 健康檢查 |
| Hearing impairment | 聽覺障礙 |
| Heart disease | 診斷欠明之心臟疾病 |
| Heart failure | 心臟衰竭 |
| Heart murmur | 心雜音 |
| Hematuria | 血尿 |
| Hemiplegia | 半身麻痺 |
| Hemolytic anemia (acquired) | 後天性溶血性貧血 |
| Hemoptysis | 咳血 |
| Hemorrhoid | 痔瘡 |
| Hepatitis B | b型肝炎 |
| Hepatitis C | c型肝炎 |
| Hepatoma | 肝惡性腫瘤,原發性 |
| Hepatomegaly | 肝腫大 |
| Herniation intervertebral disc | 椎間盤突出 |
| Herpes simplex | 單純性泡疹 |
| Herpes zoster | 帶狀泡疹 |
| Hiatal hernia | 橫膈疝氣 |
| Human immunodeficiency virus (HIV) infection | 人類免疫不全病毒感染 |
| Hoshimoto's thyroiditis | 橋本氏慢性淋巴球性甲狀腺炎 |
| Hydronephrosis | 腎水腫 |
| Hyperlipidemia | 高脂血症 |
| Hypertension, essential | 本態性高血壓 |
| Hypertension, secondary | 次發性高血壓 |
| Hypertensive heart disease | 高血壓性心臟病 |
| Hypertensive renal disease | 高血壓性腎臟疾病 |
| Hyperthyroidism | 甲狀腺亢進 |
| Hypochondriasis | 慮病症 |
| Hypothyroidism | 甲狀腺功能低下 |
| Hysteria | 歇斯底里 |
| Impetigo | 膿庖症 |
| Impotence, organic | 器質性陽萎 |
| Impotence, psychogenic | 精神性陽萎 |
| Infectious diarrhea | 感染性腹瀉 |
| Influenza | 流行性感冒 |
| Inguinal hernia | 腹股溝疝氣 |
| Insomnia | 失眠 |
| Irritable bowel syndrome | 躁性大腸徵候群 |
| Ischemic heart disease | 缺血性心臟病 |
| Jaundice | 黃疸 |
| Joint pain | 關節痛 |
| Joint stiffness | 關節僵直 |
| Joint swelling | 關節腫脹 |
| Juvenile rheumatoid artritis (polyarticular) | 多發性少年期類風濕性關節炎 |
| Keloid scar | 瘢瘤 |
| Laboratory examination | 實驗室檢查 |
| Lipoma | 脂肪瘤 |
| Liver abscess | 肝膿瘍 |
| Liver cirrhosis | 肝硬化 |
| Low back pain | 下背痛 |
| Lymphadenitis | 淋巴腺炎 |
| Lymphadenopathy | 淋巴腺病變 |
| Lymphoma | 淋巴瘤 |
| Malaise and fatigue | 倦怠及疲勞 |
| Malignant melanoma | 皮膚惡性黑色素瘤,未明示部位者 |
| Malnutrition | 營養不良 |
| Manic-depressive psychosis | 躁鬱症 |
| Mass, superficial | 局部表淺性腫脹或腫塊 |
| Measles | 麻疹 |
| Meniere's disease | 梅尼爾氏症 |
| Menigitis, aseptic | 無菌性腦膜炎 |
| Meningitis, bacterial | 細菌性腦膜炎 |
| Menopausal syndrome | 停經或女性更年期徵候群 |
| Menstruation disorder | 月經異常 |
| Mental retardation | 智能不足 |
| Migraine | 偏頭痛 |
| Myalgia and myositis | 肌痛及肌炎 |
| Nausea | 噁心 |
| Vomiting | 嘔吐 |
| Nausea and vomiting | 噁心及嘔吐 |
| Nephritis | 腎炎 |
| Nephrotic syndrome | 腎病徵候群 |
| Neuropathy, lower limb | 下肢單一神經炎 |
| Neuropathy, upper limb | 上肢單一神經炎 |
| Neurotic disorder | 精神官能症 |
| Obesity | 肥胖症 |
| Obsessive-compulsive disorder | 強迫症 |
| Old myocardial infarction | 陳舊性心肌梗塞 |
| Oral lesion | 口腔病灶 |
| Organic psychosis, chronic | 器質性腦徵候群, 慢性 |
| Osteoarthritis | 骨關節炎 |
| Osteoporosis | 骨質疏鬆症 |
| Otitis externa | 外耳炎 |
| Otitis media, suppurative | 化膿性中耳炎 |
| Palpitation | 心悸 |
| Parkinson’s disease | 帕金森氏症 |
| Paronychia, finger | 手指甲床炎與甲溝炎 |
| Paronychia, toe | 足趾甲床炎與甲溝炎 |
| Paroxysmal supraventricular tachycardia | 陣發性心室上心搏過速 |
| Pelvic inflammatory disease | 骨盆腔發炎 |
| Peptic ulcer | 消化性潰瘍 |
| Peripheral arteries occlusion disease | 末梢動脈阻塞症 |
| Peripheral neuropathy | 末梢神經疾病 |
| Peripheral vascular disease | 末梢血管疾病 |
| Pharyngitis | 急性咽喉炎 |
| Phlebitis | 靜脈炎 |
| Pityriasis versicolor | 變色糠疹 |
| Plantar fascitiis | 足底肌膜炎 |
| Pneumoconiosis | 塵肺症 |
| Pneumonia | 肺炎 |
| Polymyositis | 多發性肌炎 |
| Postural hypotension | 姿勢性低血壓 |
| Proteinuria | 蛋白尿 |
| Pruritus cutaneous | 皮膚搔癢症 |
| Psoriasis | 牛皮癬 |
| Psychophysiological disorder | 心理生理功能障礙 |
| Purpura | 紫斑症 |
| Radiculitis, cervicobrachial | 頸臂神經根炎 |
| Radiculitis, lumbosacral | 腰胝骨神經根炎 |
| Raynaud's phenomenon | 雷諾氏徵候群 |
| Reflux esophagitis | 食道炎 |
| Regional enteritis | 局部性腸炎 |
| Renal stone | 腎結石 |
| Rheumatic fever | 風濕熱 |
| Rheumatic heart disease | 風濕性心臟病 |
| Rheumatoid arthritis | 類風濕關節炎 |
| Rubella | 德國麻疹 |
| Salmonellosis | 沙門氏菌病 |
| Scabies | 疥癬(疥瘡) |
| Scarlet fever | 猩紅熱 |
| Schizophrenia | 精神分裂症 |
| Sciatica | 坐骨神經痛 |
| Sensory disturbance | 皮膚感覺障礙 |
| Sepsis | 敗血症 |
| Shigella dysenteriae | 志賀桿菌性痢疾 |
| Skin infection | 皮膚感染 |
| Skin rash | 皮疹 |
| Skin vesicular eruption | 皮膚水泡發疹 |
| Spinal stenosis, cervical | 頸部脊椎狹窄 |
| Spinal stenosis, lumbar | 腰部脊椎狹窄 |
| Spondylosis | 脊椎關節黏連 |
| Spondylosis, cervical | 頸部關節黏連 |
| Strain / sprain | 拉傷 |
| Stress incontinence, female | 壓力性排尿失禁，女性 |
| Syncope / collapse | 暈厥/虛脫 |
| Syphilis | 梅毒 |
| Systemic lupus erythematosus (SLE) | 全身紅斑性狼瘡 |
| Systemic sclerosis | 全身性硬化症 |
| Tachycardia | 心搏過速 |
| Tacycardia, proxysmal | 陣發性心搏過速 |
| Tendinitis | 肌腱炎 |
| Tension headache | 緊張性頭痛 |
| Thalassemia | 地中海型貧血 |
| Thrombocytopenia | 血小板缺乏 |
| Tinea coporis | 體癬 |
| Tinea cruris | 股癬 |
| Tinea of nail | 指(趾)癬 |
| Tinea pedis | 足癬 |
| Tinnitus | 耳鳴 |
| Transient ischemic attack | 暫時性腦部缺氧發作 |
| Trichomoniasis, genitourinary | 泌尿生殖道滴虫病 |
| Trigeminal neuralgia | 三叉神經痛 |
| Tuberculosis | 結核病 |
| Tuberculosis of pulmonary | 肺結核 |
| Typhoid fever | 傷寒 |
| Ulcer of lower limbs | 下肢潰瘍 |
| Upper respiratory infection | 上呼吸道感染 |
| Urethritis | 尿道炎 |
| Urinary tract infection | 泌尿道感染 |
| Urine incontinence | 小便失禁 |
| Urolithiasis | 尿結石 |
| Urticaria | 蕁麻疹 |
| Uterine myoma | 子宮平滑肌瘤 |
| Vaginitis | 陰道炎 |
| Varicose, lower limbs | 下肢靜脈曲張 |
| Vasculitis | 血管炎 |
| Vertigo | 眩暈徵候群 |
| Viral infection | 病毒感染 |
| Visual disturbance | 視覺障礙 |
| Vitamin B deficiency | 維生素Ｂ缺乏 |
| Vitamin C deficiency | 維生素Ｃ缺乏 |
| Weight gain, abnormal | 體重異常增加 |
| Weight loss, abnormal | 體重異常減輕 |
| Mitral Valve Prolpapse | 二尖瓣脫垂 |
內科學包含了依不同器官系統而分類的次專科：心臟內科、呼吸科、肝膽腸胃科、腎臟科（泌尿內科）、血液科、腫瘤科、內分泌科、傳染病科、免疫科、風濕科、神經科、兒科、神經內科、老年病科等，但各地甚至各醫院對次專科的分類可能有所不同。各次專科多半有成立各自的醫學會，各自審查次專科醫師的資格並舉辦學術活動。廣義的內科學更包含了皮膚科、眼科、精神醫學、復健科（康復科）、放射科、安寧緩和科、環境及職業病科等非用外科手術方式治療之專科。
