Clinical Trials by Condition: O
- Obesity (9,510)
- Obesity Hypoventilation Syndrome (52)
- Obesity, Abdominal (212)
- Obesity, Metabolically Benign (14)
- Obesity, Morbid (726)
- Obsessive Behavior (2)
- Obsessive-Compulsive Disorder (444)
- Obstetric Labor Complications (2,349)
- Obstetric Labor, Premature (1,786)
- Occipital Horn Syndrome (1)
- Occupational Diseases (338)
- Occupational Injuries (9)
- Occupational Stress (176)
- Ochronosis (9)
- Ocular Cicatricial Pemphigoid (4)
- Ocular Hypertension (1,558)
- Ocular Hypotension (7)
- Ocular Melanoma (53)
- Ocular Motility Disorders (302)
- Ocular Muscular Dystrophy (5)
- Ocular Toxoplasmosis (4)
- Oculocerebral Syndrome With Hypopigmentation (4,345)
- Oculocerebrorenal Syndrome (5)
- Oculocutaneous Albinism (14)
- Oculomotor Nerve Diseases (4)
- Oculopharyngeal Muscular Dystrophy (12)
- Odontogenic Tumors (4)
- Ogilvie Syndrome (2)
- Olfaction Disorders (53)
- Olfactory Nerve Diseases (18)
- Olfactory Nerve Injuries (2)
- Olfactory Neuroblastoma (65)
- Oligoastrocytoma (96)
- Oligodendroglioma (373)
- Oligohydramnios (23)
- Oligomenorrhea (9)
- Oligospermia (32)
- Oliguria (11)
- Olivopontocerebellar Atrophies (2)
- Ollier Disease (8)
- Omenn Syndrome (6)
- Onchocerciasis (24)
- Onchocerciasis, Ocular (6)
- Oncogenic Osteomalacia (13)
- Onycholysis (5)
- Onychomycosis (119)
- Open Bite (10)
- Ophthalmia Neonatorum (2)
- Ophthalmoplegia (119)
- Ophthalmoplegia, Chronic Progressive External (9)
- Opioid-Related Disorders (652)
- Opportunistic Infections (210)
- Opsoclonus-Myoclonus Syndrome (6)
- Optic Atrophies, Hereditary (38)
- Optic Atrophy (48)
- Optic Atrophy 1 (5)
- Optic Atrophy, Autosomal Dominant (5)
- Optic Atrophy, Hereditary, Leber (32)
- Optic Disk Drusen (2)
- Optic Nerve Diseases (339)
- Optic Nerve Glioma (17)
- Optic Nerve Injuries (14)
- Optic Nerve Neoplasms (18)
- Optic Neuritis (133)
- Optic Neuropathy, Ischemic (44)
- Optic Pathway Glioma (42)
- Oral Cancer (474)
- Oral Hemorrhage (14)
- Oral Leukoplakia (31)
- Oral Manifestations (24)
- Oral Squamous Cell Carcinoma (165)
- Oral Submucous Fibrosis (9)
- Oral Ulcer (35)
- Orbital Cellulitis (3)
- Orbital Diseases (165)
- Orbital Fractures (15)
- Orbital Lymphoma (2)
- Orbital Neoplasms (8)
- Orbital Pseudotumor (4)
- Orchitis (3)
- Organic Acidemias (12)
- Organophosphate Poisoning (10)
- Ornithine Carbamoyltransferase Deficiency Disease (22)
- Ornithine Transcarbamylase Deficiency (22)
- Orofaciodigital Syndromes (2)
- Oropharyngeal Cancer, Adult (10)
- Oropharyngeal Neoplasms (251)
- Orotic Aciduria Type 1 (1)
- Orthomyxoviridae Infections (1,752)
- Orthostatic Intolerance (238)
- Ossification of Posterior Longitudinal Ligament (5)
- Ossification, Heterotopic (32)
- Osteitis (35)
- Osteitis Deformans (15)
- Osteoarthritis (4,175)
- Osteoarthritis, Hip (452)
- Osteoarthritis, Knee (2,285)
- Osteoarthritis, Spine (13)
- Osteoarthropathy, Primary Hypertrophic (2)
- Osteoarthropathy, Secondary Hypertrophic (1)
- Osteoblastoma (1)
- Osteochondritis (30)
- Osteochondritis Dissecans (26)
- Osteochondrodysplasias (198)
- Osteochondroma (22)
- Osteochondromatosis (13)
- Osteochondrosis (29)
- Osteofibrous Dysplasia (1)
- Osteogenesis Imperfecta (56)
- Osteogenesis Imperfecta Type II (1)
- Osteogenesis Imperfecta Type III (10)
- Osteogenesis Imperfecta Type IV (2)
- Osteogenesis Imperfecta Type VI (4)
- Osteolysis (23)
- Osteolysis, Essential (3)
- Osteoma (8)
- Osteoma, Osteoid (8)
- Osteomalacia (44)
- Osteomyelitis (89)
- Osteonecrosis (142)
- Osteopetrosis (21)
- Osteopetrosis Autosomal Dominant Type 2 (1)
- Osteophyte (24)
- Osteoporosis (1,427)
- Osteoporosis, Postmenopausal (278)
- Osteoporosis-pseudoglioma Syndrome (2)
- Osteoporotic Fractures (78)
- Osteoradionecrosis (16)
- Osteosarcoma (556)
- Osteosarcoma, Juxtacortical (1)
- Osteosclerosis (25)
- Ostium Secundum Atrial Septal Defect (7)
- Otitis (317)
- Otitis Externa (25)
- Otitis Media (250)
- Otitis Media with Effusion (67)
- Otitis Media, Suppurative (10)
- Oto-Palatal-digital Syndrome (2)
- Oto-palato-digital Syndrome Type 1 (2)
- Otomycosis (9)
- Otorhinolaryngologic Diseases (4,936)
- Otorhinolaryngologic Neoplasms (964)
- Otosclerosis (12)
- Out-of-Hospital Cardiac Arrest (228)
- Ovarian Cancer (2,765)
- Ovarian Carcinosarcoma (28)
- Ovarian Cysts (654)
- Ovarian Diseases (2,681)
- Ovarian Epithelial Cancer (2,588)
- Ovarian Germ Cell Tumor (185)
- Ovarian Hyperstimulation Syndrome (70)
- Ovarian Low Malignant Potential Tumor (25)
- Ovarian Neoplasms (2,716)
- Ovarian Sex Cord Tumor With Annular Tubules (5)
- Ovarian Small Cell Carcinoma (3)
- Overbite (59)
- Overnutrition (3,796)
- Overweight (5,619)