Clinical Trials by Condition: O
- Obesity (10,564)
- Obesity Hypoventilation Syndrome (57)
- Obesity, Abdominal (240)
- Obesity, Maternal (54)
- Obesity, Metabolically Benign (19)
- Obesity, Morbid (808)
- Obsessive Behavior (2)
- Obsessive-Compulsive Disorder (494)
- Obstetric Labor Complications (2,658)
- Obstetric Labor, Premature (2,017)
- Occipital Horn Syndrome (2)
- Occupational Diseases (432)
- Occupational Injuries (10)
- Occupational Stress (243)
- Ochronosis (9)
- Ocular Cicatricial Pemphigoid (4)
- Ocular Hypertension (1,712)
- Ocular Hypotension (8)
- Ocular Melanoma (62)
- Ocular Motility Disorders (341)
- Ocular Muscular Dystrophy (7)
- Ocular Toxoplasmosis (4)
- Oculo-auriculo-vertebral Spectrum (9)
- Oculocerebral Syndrome With Hypopigmentation (4,921)
- Oculocerebrorenal Syndrome (6)
- Oculocutaneous Albinism (14)
- Oculomotor Nerve Diseases (4)
- Oculopharyngeal Muscular Dystrophy (12)
- Odontogenic Cysts (36)
- Odontogenic Tumors (7)
- Odontoma (1)
- Ogilvie Syndrome (3)
- Olfaction Disorders (79)
- Olfactory Nerve Diseases (19)
- Olfactory Nerve Injuries (2)
- Olfactory Neuroblastoma (66)
- Oligoastrocytoma (98)
- Oligodendroglioma (385)
- Oligohydramnios (27)
- Oligomenorrhea (11)
- Oligospermia (39)
- Oliguria (12)
- Olivopontocerebellar Atrophies (3)
- Ollier Disease (8)
- Omenn Syndrome (6)
- Onchocerciasis (28)
- Onchocerciasis, Ocular (8)
- Oncogenic Osteomalacia (14)
- Onycholysis (5)
- Onychomycosis (134)
- Open Bite (14)
- Ophthalmia Neonatorum (2)
- Ophthalmoplegia (135)
- Ophthalmoplegia, Chronic Progressive External (11)
- Opiate Overdose (58)
- Opioid-Induced Constipation (100)
- Opioid-Related Disorders (1,104)
- Opisthorchiasis (1)
- Opportunistic Infections (215)
- Opsoclonus-Myoclonus Syndrome (6)
- Optic Atrophies, Hereditary (41)
- Optic Atrophy (52)
- Optic Atrophy 1 (5)
- Optic Atrophy, Autosomal Dominant (5)
- Optic Atrophy, Hereditary, Leber (34)
- Optic Disk Drusen (3)
- Optic Nerve Diseases (387)
- Optic Nerve Glioma (18)
- Optic Nerve Hypoplasia (3)
- Optic Nerve Injuries (19)
- Optic Nerve Neoplasms (20)
- Optic Neuritis (160)
- Optic Neuropathy, Ischemic (47)
- Optic Pathway Glioma (43)
- Oral Cancer (536)
- Oral Hemorrhage (16)
- Oral Leukoplakia (33)
- Oral Manifestations (27)
- Oral Squamous Cell Carcinoma (184)
- Oral Submucous Fibrosis (9)
- Oral Ulcer (47)
- Orbital Cellulitis (3)
- Orbital Diseases (196)
- Orbital Fractures (17)
- Orbital Lymphoma (2)
- Orbital Neoplasms (9)
- Orbital Pseudotumor (4)
- Orchitis (5)
- Organic Acidemias (16)
- Organophosphate Poisoning (10)
- Ornithine Carbamoyltransferase Deficiency Disease (27)
- Ornithine Transcarbamylase Deficiency (29)
- Oroantral Fistula (3)
- Orofaciodigital Syndromes (2)
- Oropharyngeal Cancer, Adult (10)
- Oropharyngeal Neoplasms (281)
- Orotic Aciduria Type 1 (1)
- Orthomyxoviridae Infections (1,880)
- Orthostatic Intolerance (275)
- Ossification of Posterior Longitudinal Ligament (11)
- Ossification, Heterotopic (43)
- Osteitis (40)
- Osteitis Deformans (16)
- Osteoarthritis (4,709)
- Osteoarthritis, Hip (515)
- Osteoarthritis, Knee (2,646)
- Osteoarthritis, Spine (13)
- Osteoarthropathy, Primary Hypertrophic (2)
- Osteoarthropathy, Secondary Hypertrophic (1)
- Osteoblastoma (1)
- Osteochondritis (31)
- Osteochondritis Dissecans (27)
- Osteochondrodysplasias (225)
- Osteochondroma (27)
- Osteochondromatosis (13)
- Osteochondrosis (33)
- Osteofibrous Dysplasia (1)
- Osteogenesis Imperfecta (63)
- Osteogenesis Imperfecta Type II (1)
- Osteogenesis Imperfecta Type III (10)
- Osteogenesis Imperfecta Type IV (2)
- Osteogenesis Imperfecta Type VI (4)
- Osteolysis (25)
- Osteolysis, Essential (3)
- Osteoma (10)
- Osteoma, Osteoid (8)
- Osteomalacia (46)
- Osteomyelitis (100)
- Osteonecrosis (150)
- Osteopetrosis (20)
- Osteopetrosis Autosomal Dominant Type 2 (1)
- Osteophyte (28)
- Osteoporosis (1,542)
- Osteoporosis, Postmenopausal (310)
- Osteoporosis-pseudoglioma Syndrome (2)
- Osteoporotic Fractures (89)
- Osteoradionecrosis (19)
- Osteosarcoma (615)
- Osteosarcoma, Juxtacortical (2)
- Osteosclerosis (27)
- Ostium Secundum Atrial Septal Defect (7)
- Otitis (336)
- Otitis Externa (27)
- Otitis Media (262)
- Otitis Media with Effusion (73)
- Otitis Media, Suppurative (12)
- Oto-Palatal-digital Syndrome (2)
- Oto-palato-digital Syndrome Type 1 (2)
- Otomycosis (9)
- Otorhinolaryngologic Diseases (5,643)
- Otorhinolaryngologic Neoplasms (1,113)
- Otosclerosis (15)
- Ototoxicity (42)
- Out-of-Hospital Cardiac Arrest (265)
- Ovarian Cancer (3,085)
- Ovarian Carcinosarcoma (31)
- Ovarian Cysts (733)
- Ovarian Diseases (3,012)
- Ovarian Epithelial Cancer (2,881)
- Ovarian Germ Cell Tumor (186)
- Ovarian Hyperstimulation Syndrome (73)
- Ovarian Low Malignant Potential Tumor (25)
- Ovarian Neoplasms (3,035)
- Ovarian Sex Cord Tumor With Annular Tubules (5)
- Ovarian Small Cell Carcinoma (4)
- Ovarian Torsion (10)
- Overbite (80)
- Overnutrition (4,297)
- Overweight (6,313)