Clinical Trials by Condition: O
- Obesity (10,832)
- Obesity Hypoventilation Syndrome (57)
- Obesity, Abdominal (248)
- Obesity, Maternal (57)
- Obesity, Metabolically Benign (19)
- Obesity, Morbid (828)
- Obsessive Behavior (2)
- Obsessive-Compulsive Disorder (510)
- Obstetric Labor Complications (2,730)
- Obstetric Labor, Premature (2,072)
- Occipital Horn Syndrome (2)
- Occupational Diseases (463)
- Occupational Injuries (12)
- Occupational Stress (266)
- Ochronosis (9)
- Ocular Cicatricial Pemphigoid (4)
- Ocular Hypertension (1,748)
- Ocular Hypotension (8)
- Ocular Melanoma (64)
- Ocular Motility Disorders (348)
- Ocular Muscular Dystrophy (7)
- Ocular Toxoplasmosis (4)
- Oculo-auriculo-vertebral Spectrum (10)
- Oculocerebral Syndrome With Hypopigmentation (5,066)
- 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 (81)
- Olfactory Nerve Diseases (19)
- Olfactory Nerve Injuries (2)
- Olfactory Neuroblastoma (66)
- Oligoastrocytoma (99)
- Oligodendroglioma (391)
- Oligohydramnios (28)
- Oligomenorrhea (11)
- Oligospermia (40)
- Oliguria (12)
- Olivopontocerebellar Atrophies (3)
- Ollier Disease (8)
- Omenn Syndrome (6)
- Onchocerciasis (28)
- Onchocerciasis, Ocular (8)
- Oncogenic Osteomalacia (14)
- Onycholysis (5)
- Onychomycosis (139)
- Open Bite (16)
- Ophthalmia Neonatorum (2)
- Ophthalmoplegia (138)
- Ophthalmoplegia, Chronic Progressive External (12)
- Opiate Overdose (61)
- Opioid-Induced Constipation (101)
- Opioid-Related Disorders (1,146)
- Opisthorchiasis (1)
- Opportunistic Infections (219)
- Opsoclonus-Myoclonus Syndrome (6)
- Optic Atrophies, Hereditary (44)
- Optic Atrophy (55)
- Optic Atrophy 1 (5)
- Optic Atrophy, Autosomal Dominant (5)
- Optic Atrophy, Hereditary, Leber (35)
- Optic Disk Drusen (3)
- Optic Nerve Diseases (399)
- Optic Nerve Glioma (18)
- Optic Nerve Hypoplasia (3)
- Optic Nerve Injuries (19)
- Optic Nerve Neoplasms (20)
- Optic Neuritis (166)
- Optic Neuropathy, Ischemic (47)
- Optic Pathway Glioma (43)
- Oral Cancer (544)
- Oral Hemorrhage (16)
- Oral Leukoplakia (33)
- Oral Manifestations (30)
- Oral Squamous Cell Carcinoma (189)
- Oral Submucous Fibrosis (10)
- Oral Ulcer (47)
- Orbital Cellulitis (3)
- Orbital Diseases (203)
- Orbital Fractures (17)
- Orbital Lymphoma (2)
- Orbital Neoplasms (11)
- Orbital Pseudotumor (4)
- Orchitis (5)
- Organic Acidemias (16)
- Organophosphate Poisoning (10)
- Ornithine Carbamoyltransferase Deficiency Disease (28)
- Ornithine Transcarbamylase Deficiency (30)
- Oroantral Fistula (3)
- Orofaciodigital Syndromes (2)
- Oropharyngeal Cancer, Adult (10)
- Oropharyngeal Neoplasms (286)
- Orotic Aciduria Type 1 (1)
- Orthomyxoviridae Infections (1,907)
- Orthostatic Intolerance (290)
- Ossification of Posterior Longitudinal Ligament (11)
- Ossification, Heterotopic (45)
- Osteitis (42)
- Osteitis Deformans (16)
- Osteoarthritis (4,829)
- Osteoarthritis, Hip (531)
- Osteoarthritis, Knee (2,731)
- Osteoarthritis, Spine (14)
- Osteoarthropathy, Primary Hypertrophic (2)
- Osteoarthropathy, Secondary Hypertrophic (1)
- Osteoblastoma (1)
- Osteochondritis (32)
- Osteochondritis Dissecans (27)
- Osteochondrodysplasias (232)
- Osteochondroma (28)
- Osteochondromatosis (13)
- Osteochondrosis (34)
- Osteofibrous Dysplasia (1)
- Osteogenesis Imperfecta (65)
- Osteogenesis Imperfecta Type II (1)
- Osteogenesis Imperfecta Type III (11)
- Osteogenesis Imperfecta Type IV (2)
- Osteogenesis Imperfecta Type VI (5)
- Osteolysis (26)
- Osteolysis, Essential (3)
- Osteoma (11)
- Osteoma, Osteoid (9)
- Osteomalacia (47)
- Osteomyelitis (105)
- Osteonecrosis (155)
- Osteopetrosis (20)
- Osteopetrosis Autosomal Dominant Type 2 (1)
- Osteophyte (30)
- Osteoporosis (1,564)
- Osteoporosis, Postmenopausal (319)
- Osteoporosis-pseudoglioma Syndrome (2)
- Osteoporotic Fractures (89)
- Osteoradionecrosis (19)
- Osteosarcoma (621)
- Osteosarcoma, Juxtacortical (2)
- Osteosclerosis (27)
- Ostium Secundum Atrial Septal Defect (7)
- Otitis (345)
- Otitis Externa (27)
- Otitis Media (268)
- Otitis Media with Effusion (74)
- Otitis Media, Suppurative (14)
- Oto-Palatal-digital Syndrome (3)
- Oto-palato-digital Syndrome Type 1 (3)
- Otomycosis (10)
- Otorhinolaryngologic Diseases (5,825)
- Otorhinolaryngologic Neoplasms (1,150)
- Otosclerosis (16)
- Ototoxicity (46)
- Out-of-Hospital Cardiac Arrest (273)
- Ovarian Cancer (3,154)
- Ovarian Carcinosarcoma (32)
- Ovarian Cysts (747)
- Ovarian Diseases (3,084)
- Ovarian Epithelial Cancer (2,944)
- Ovarian Germ Cell Tumor (186)
- Ovarian Hyperstimulation Syndrome (75)
- Ovarian Low Malignant Potential Tumor (25)
- Ovarian Neoplasms (3,104)
- Ovarian Sex Cord Tumor With Annular Tubules (5)
- Ovarian Small Cell Carcinoma (4)
- Ovarian Torsion (10)
- Overbite (93)
- Overnutrition (4,432)
- Overweight (6,496)