Clinical Trials by Condition: O
- Obesity (9,651)
- Obesity Hypoventilation Syndrome (53)
- Obesity, Abdominal (221)
- Obesity, Metabolically Benign (14)
- Obesity, Morbid (740)
- Obsessive Behavior (2)
- Obsessive-Compulsive Disorder (457)
- Obstetric Labor Complications (2,379)
- Obstetric Labor, Premature (1,811)
- Occipital Horn Syndrome (1)
- Occupational Diseases (355)
- Occupational Injuries (9)
- Occupational Stress (190)
- Ochronosis (9)
- Ocular Cicatricial Pemphigoid (4)
- Ocular Hypertension (1,584)
- Ocular Hypotension (7)
- Ocular Melanoma (53)
- Ocular Motility Disorders (310)
- Ocular Muscular Dystrophy (5)
- Ocular Toxoplasmosis (4)
- Oculocerebral Syndrome With Hypopigmentation (4,418)
- Oculocerebrorenal Syndrome (6)
- Oculocutaneous Albinism (14)
- Oculomotor Nerve Diseases (4)
- Oculopharyngeal Muscular Dystrophy (12)
- Odontogenic Tumors (4)
- Ogilvie Syndrome (3)
- Olfaction Disorders (55)
- Olfactory Nerve Diseases (18)
- Olfactory Nerve Injuries (2)
- Olfactory Neuroblastoma (65)
- Oligoastrocytoma (97)
- Oligodendroglioma (374)
- Oligohydramnios (23)
- Oligomenorrhea (10)
- Oligospermia (34)
- Oliguria (11)
- Olivopontocerebellar Atrophies (2)
- Ollier Disease (8)
- Omenn Syndrome (6)
- Onchocerciasis (26)
- Onchocerciasis, Ocular (7)
- Oncogenic Osteomalacia (13)
- Onycholysis (5)
- Onychomycosis (121)
- Open Bite (11)
- Ophthalmia Neonatorum (2)
- Ophthalmoplegia (122)
- Ophthalmoplegia, Chronic Progressive External (9)
- Opioid-Related Disorders (654)
- Opportunistic Infections (210)
- Opsoclonus-Myoclonus Syndrome (6)
- Optic Atrophies, Hereditary (41)
- Optic Atrophy (51)
- Optic Atrophy 1 (5)
- Optic Atrophy, Autosomal Dominant (5)
- Optic Atrophy, Hereditary, Leber (34)
- Optic Disk Drusen (2)
- Optic Nerve Diseases (346)
- Optic Nerve Glioma (17)
- Optic Nerve Injuries (14)
- Optic Nerve Neoplasms (18)
- Optic Neuritis (135)
- Optic Neuropathy, Ischemic (44)
- Optic Pathway Glioma (42)
- Oral Cancer (484)
- Oral Hemorrhage (15)
- Oral Leukoplakia (31)
- Oral Manifestations (25)
- Oral Squamous Cell Carcinoma (167)
- Oral Submucous Fibrosis (9)
- Oral Ulcer (36)
- Orbital Cellulitis (3)
- Orbital Diseases (169)
- Orbital Fractures (15)
- Orbital Lymphoma (2)
- Orbital Neoplasms (8)
- Orbital Pseudotumor (4)
- Orchitis (3)
- Organic Acidemias (13)
- Organophosphate Poisoning (10)
- Ornithine Carbamoyltransferase Deficiency Disease (24)
- Ornithine Transcarbamylase Deficiency (24)
- Orofaciodigital Syndromes (2)
- Oropharyngeal Cancer, Adult (10)
- Oropharyngeal Neoplasms (256)
- Orotic Aciduria Type 1 (1)
- Orthomyxoviridae Infections (1,760)
- Orthostatic Intolerance (242)
- Ossification of Posterior Longitudinal Ligament (7)
- Ossification, Heterotopic (35)
- Osteitis (36)
- Osteitis Deformans (15)
- Osteoarthritis (4,240)
- Osteoarthritis, Hip (460)
- Osteoarthritis, Knee (2,332)
- Osteoarthritis, Spine (13)
- Osteoarthropathy, Primary Hypertrophic (2)
- Osteoarthropathy, Secondary Hypertrophic (1)
- Osteoblastoma (1)
- Osteochondritis (30)
- Osteochondritis Dissecans (26)
- Osteochondrodysplasias (199)
- Osteochondroma (22)
- Osteochondromatosis (13)
- Osteochondrosis (30)
- 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 (9)
- Osteoma, Osteoid (8)
- Osteomalacia (44)
- Osteomyelitis (91)
- Osteonecrosis (144)
- Osteopetrosis (21)
- Osteopetrosis Autosomal Dominant Type 2 (1)
- Osteophyte (24)
- Osteoporosis (1,442)
- Osteoporosis, Postmenopausal (282)
- Osteoporosis-pseudoglioma Syndrome (2)
- Osteoporotic Fractures (80)
- Osteoradionecrosis (17)
- Osteosarcoma (568)
- Osteosarcoma, Juxtacortical (1)
- Osteosclerosis (25)
- Ostium Secundum Atrial Septal Defect (7)
- Otitis (320)
- Otitis Externa (26)
- Otitis Media (251)
- 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 (5,035)
- Otorhinolaryngologic Neoplasms (987)
- Otosclerosis (14)
- Out-of-Hospital Cardiac Arrest (229)
- Ovarian Cancer (2,799)
- Ovarian Carcinosarcoma (29)
- Ovarian Cysts (661)
- Ovarian Diseases (2,718)
- Ovarian Epithelial Cancer (2,620)
- Ovarian Germ Cell Tumor (185)
- Ovarian Hyperstimulation Syndrome (70)
- Ovarian Low Malignant Potential Tumor (25)
- Ovarian Neoplasms (2,750)
- Ovarian Sex Cord Tumor With Annular Tubules (5)
- Ovarian Small Cell Carcinoma (3)
- Overbite (61)
- Overnutrition (3,862)
- Overweight (5,711)