Clinical Trials by Condition: O
- Obesity (8,598)
- Obesity Hypoventilation Syndrome (45)
- Obesity, Abdominal (189)
- Obesity, Metabolically Benign (10)
- Obesity, Morbid (636)
- Obsessive Behavior (1)
- Obsessive-Compulsive Disorder (411)
- Obstetric Labor Complications (2,079)
- Obstetric Labor, Premature (1,591)
- Occipital Horn Syndrome (1)
- Occupational Diseases (261)
- Occupational Injuries (8)
- Occupational Stress (122)
- Ochronosis (7)
- Ocular Cicatricial Pemphigoid (4)
- Ocular Hypertension (1,405)
- Ocular Hypotension (7)
- Ocular Melanoma (51)
- Ocular Motility Disorders (262)
- Ocular Muscular Dystrophy (3)
- Ocular Toxoplasmosis (4)
- Oculocerebrorenal Syndrome (5)
- Oculocutaneous Albinism (14)
- Oculomotor Nerve Diseases (4)
- Oculopharyngeal Muscular Dystrophy (12)
- Odontogenic Tumors (4)
- Ogilvie Syndrome (1)
- Olfaction Disorders (15)
- Olfactory Nerve Injuries (1)
- Olfactory Neuroblastoma (64)
- Oligoastrocytoma (92)
- Oligodendroglioma (365)
- Oligohydramnios (19)
- Oligomenorrhea (7)
- Oligospermia (28)
- Oliguria (9)
- Olivopontocerebellar Atrophies (2)
- Ollier Disease (7)
- Omenn Syndrome (5)
- Onchocerciasis (24)
- Onchocerciasis, Ocular (6)
- Oncogenic Osteomalacia (11)
- Onycholysis (5)
- Onychomycosis (117)
- Open Bite (7)
- Ophthalmia Neonatorum (2)
- Ophthalmoplegia (97)
- Ophthalmoplegia, Chronic Progressive External (8)
- Opioid-Related Disorders (624)
- Opportunistic Infections (207)
- Opsoclonus-Myoclonus Syndrome (6)
- Optic Atrophies, Hereditary (36)
- Optic Atrophy (42)
- Optic Atrophy 1 (5)
- Optic Atrophy, Autosomal Dominant (5)
- Optic Atrophy, Hereditary, Leber (30)
- Optic Disk Drusen (2)
- Optic Nerve Diseases (306)
- Optic Nerve Glioma (17)
- Optic Nerve Injuries (14)
- Optic Nerve Neoplasms (18)
- Optic Neuritis (119)
- Optic Neuropathy, Ischemic (43)
- Optic Pathway Glioma (43)
- Oral Cancer (432)
- Oral Hemorrhage (12)
- Oral Leukoplakia (27)
- Oral Manifestations (18)
- Oral Squamous Cell Carcinoma (40)
- Oral Submucous Fibrosis (7)
- Oral Ulcer (29)
- Orbital Cellulitis (2)
- Orbital Diseases (145)
- Orbital Fractures (14)
- Orbital Lymphoma (2)
- Orbital Neoplasms (7)
- Orbital Pseudotumor (4)
- Orchitis (2)
- Organic Acidemias (10)
- Organophosphate Poisoning (9)
- Ornithine Carbamoyltransferase Deficiency Disease (17)
- Ornithine Transcarbamylase Deficiency (17)
- Orofaciodigital Syndromes (2)
- Oropharyngeal Cancer, Adult (9)
- Oropharyngeal Neoplasms (224)
- Orotic Aciduria Type 1 (1)
- Orthomyxoviridae Infections (1,675)
- Orthostatic Intolerance (215)
- Ossification of Posterior Longitudinal Ligament (4)
- Ossification, Heterotopic (28)
- Osteitis (31)
- Osteitis Deformans (15)
- Osteoarthritis (3,716)
- Osteoarthritis, Hip (390)
- Osteoarthritis, Knee (1,982)
- Osteoarthritis, Spine (11)
- Osteoarthropathy, Primary Hypertrophic (2)
- Osteoarthropathy, Secondary Hypertrophic (1)
- Osteoblastoma (1)
- Osteochondritis (27)
- Osteochondritis Dissecans (24)
- Osteochondrodysplasias (182)
- Osteochondroma (18)
- Osteochondromatosis (13)
- Osteochondrosis (26)
- Osteofibrous Dysplasia (1)
- Osteogenesis Imperfecta (51)
- Osteogenesis Imperfecta Type II (1)
- Osteogenesis Imperfecta Type III (8)
- Osteogenesis Imperfecta Type IV (1)
- Osteogenesis Imperfecta Type VI (3)
- Osteolysis (23)
- Osteolysis, Essential (3)
- Osteoma (6)
- Osteoma, Osteoid (6)
- Osteomalacia (40)
- Osteomyelitis (79)
- Osteonecrosis (132)
- Osteopetrosis (19)
- Osteopetrosis Autosomal Dominant Type 2 (1)
- Osteophyte (20)
- Osteoporosis (1,344)
- Osteoporosis, Postmenopausal (255)
- Osteoporosis-pseudoglioma Syndrome (2)
- Osteoporotic Fractures (71)
- Osteoradionecrosis (14)
- Osteosarcoma (500)
- Osteosarcoma, Juxtacortical (1)
- Osteosclerosis (22)
- Ostium Secundum Atrial Septal Defect (5)
- Otitis (291)
- Otitis Externa (24)
- Otitis Media (231)
- Otitis Media with Effusion (63)
- Otitis Media, Suppurative (8)
- Oto-Palatal-digital Syndrome (2)
- Oto-palato-digital Syndrome Type 1 (2)
- Otomycosis (6)
- Otorhinolaryngologic Diseases (4,382)
- Otorhinolaryngologic Neoplasms (848)
- Otosclerosis (12)
- Out-of-Hospital Cardiac Arrest (197)
- Ovarian Cancer (2,511)
- Ovarian Carcinosarcoma (27)
- Ovarian Cysts (601)
- Ovarian Diseases (2,426)
- Ovarian Epithelial Cancer (2,357)
- Ovarian Germ Cell Tumor (184)
- Ovarian Hyperstimulation Syndrome (68)
- Ovarian Low Malignant Potential Tumor (25)
- Ovarian Neoplasms (2,462)
- Ovarian Sex Cord Tumor With Annular Tubules (5)
- Ovarian Small Cell Carcinoma (2)
- Overbite (44)
- Overnutrition (3,388)
- Overweight (5,036)