See Conditions by First Letter (B)
- B Cell Prolymphocytic Leukemia
- B-cell Lymphomas
- Babesiosis
- Back Injuries
- Back Pain
- Bacteremia
- Bacterial Infections
- Bacterial Meningitis
- Bacteriuria
- Balo Disease
- Balo's Concentric Sclerosis
- Bardet-Biedl Syndrome
- Bare Lymphocyte Syndrome
- Bare Lymphocyte Syndrome 2
- Barotrauma
- Barraquer-Simons Syndrome
- Barrett Esophagus
- Barth Syndrome
- Bartonella Infections
- Bartter Syndrome
- Basal Cell Carcinoma, Multiple
- Basal Cell Nevus Syndrome
- Basal Ganglia Diseases
- Basilar Migraine
- Batten Disease
- Becker Muscular Dystrophy
- Becker's Nevus
- Behavior, Addictive
- Behavioral Symptoms
- Behcet Syndrome
- Behcet's Disease
- Bell Palsy
- Benign Paroxysmal Positional Vertigo
- Berger Disease
- Beriberi
- Berylliosis
- Best Vitelliform Macular Dystrophy
- Beta-galactosidase-1 Deficiency
- Beta-Thalassemia
- Bethlem Myopathy
- Bile Duct Cancer
- Bile Duct Diseases
- Bile Duct Neoplasms
- Bile Reflux
- Biliary Atresia
- Biliary Dyskinesia
- Biliary Fistula
- Biliary Tract Cancer
- Biliary Tract Diseases
- Biliary Tract Neoplasms
- Binge-Eating Disorder
- Biotinidase Deficiency
- Bipolar Disorder
- Birdshot Chorioretinopathy
- Birt-Hogg-Dube Syndrome
- Birth Injuries
- Birth Weight
- Bites and Stings
- BK-virus Nephropathy
- Bladder Exstrophy
- Blast Crisis
- Blast Injuries
- Blastic Plasmacytoid Dendritic Cell
- Blastocystis Infections
- Blastoma
- Blastomycosis
- Blepharitis
- Blepharoptosis
- Blepharospasm
- Blind Loop Syndrome
- Blindness
- Blister
- Blood Coagulation Disorders
- Blood Coagulation Disorders, Inherited
- Blood Group Incompatibility
- Blood Loss, Surgical
- Blood Platelet Disorders
- Blood Protein Disorders
- Bloom Syndrome
- Body Dysmorphic Disorders
- Body Weight
- Body Weight Changes
- Bone Cancer
- Bone Cysts
- Bone Demineralization, Pathologic
- Bone Diseases
- Bone Diseases, Developmental
- Bone Diseases, Endocrine
- Bone Diseases, Metabolic
- Bone Marrow Diseases
- Bone Marrow Neoplasms
- Bone Neoplasms
- Bone Resorption
- Borderline Personality Disorder
- Borrelia Infections
- Botulism
- Bourneville Syndrome
- Bowen's Disease
- Brachial Plexus Neuritis
- Brachial Plexus Neuropathies
- Bradycardia
- Brain Concussion
- Brain Damage, Chronic
- Brain Death
- Brain Diseases
- Brain Diseases, Metabolic
- Brain Diseases, Metabolic, Inborn
- Brain Edema
- Brain Hemorrhage, Traumatic
- Brain Infarction
- Brain Injuries
- Brain Injury, Chronic
- Brain Ischemia
- Brain Neoplasms
- Brain Stem Glioma, Childhood
- Brain Stem Infarctions
- Brain Stem Neoplasms
- Brain Tumor, Adult
- Brain Tumor, Childhood
- Breast Cancer, Male
- Breast Cyst
- Breast Diseases
- Breast Neoplasms
- Breast Neoplasms, Male
- Breech Presentation
- Brenner Tumor
- Brenner Tumor of Ovary
- Brittle Cornea Syndrome
- Bronchial Diseases
- Bronchial Hyperreactivity
- Bronchial Neoplasms
- Bronchial Spasm
- Bronchiectasis
- Bronchiolitis
- Bronchiolitis Obliterans
- Bronchiolitis Obliterans Organizing Pneumonia
- Bronchiolitis, Viral
- Bronchitis
- Bronchitis, Chronic
- Bronchopneumonia
- Bronchopulmonary Dysplasia
- Brown-Sequard Syndrome
- Brucellosis
- Brugada Syndrome
- Bruxism
- Budd-Chiari Syndrome
- Buerger Disease
- Bulbo-Spinal Atrophy, X-Linked
- Bulimia
- Bulimia Nervosa
- Bullous Pemphigoid
- Bullying
- Bundle-Branch Block
- Burkholderia Infections
- Burkitt Lymphoma
- Burnett Schwartz Berberian Syndrome
- Burning Mouth Syndrome
- Burns
- Burns, Chemical
- Burns, Electric
- Bursitis
- Buruli Ulcer