Clinical Trials by Condition: O
- Obesity (9,333)
- Obesity Hypoventilation Syndrome (50)
- Obesity, Abdominal (206)
- Obesity, Metabolically Benign (14)
- Obesity, Morbid (707)
- Obsessive Behavior (2)
- Obsessive-Compulsive Disorder (438)
- Obstetric Labor Complications (2,295)
- Obstetric Labor, Premature (1,740)
- Occipital Horn Syndrome (1)
- Occupational Diseases (322)
- Occupational Injuries (9)
- Occupational Stress (166)
- Ochronosis (9)
- Ocular Cicatricial Pemphigoid (4)
- Ocular Hypertension (1,543)
- Ocular Hypotension (7)
- Ocular Melanoma (52)
- Ocular Motility Disorders (294)
- Ocular Muscular Dystrophy (5)
- Ocular Toxoplasmosis (4)
- Oculocerebral Syndrome With Hypopigmentation (4,252)
- Oculocerebrorenal Syndrome (5)
- Oculocutaneous Albinism (14)
- Oculomotor Nerve Diseases (4)
- Oculopharyngeal Muscular Dystrophy (12)
- Odontogenic Tumors (4)
- Ogilvie Syndrome (2)
- Olfaction Disorders (46)
- Olfactory Nerve Diseases (18)
- Olfactory Nerve Injuries (2)
- Olfactory Neuroblastoma (65)
- Oligoastrocytoma (96)
- Oligodendroglioma (372)
- Oligohydramnios (21)
- Oligomenorrhea (9)
- Oligospermia (31)
- Oliguria (11)
- Olivopontocerebellar Atrophies (2)
- Ollier Disease (7)
- Omenn Syndrome (6)
- Onchocerciasis (24)
- Onchocerciasis, Ocular (6)
- Oncogenic Osteomalacia (12)
- Onycholysis (5)
- Onychomycosis (119)
- Open Bite (10)
- Ophthalmia Neonatorum (2)
- Ophthalmoplegia (117)
- Ophthalmoplegia, Chronic Progressive External (9)
- Opioid-Related Disorders (646)
- Opportunistic Infections (209)
- 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 (335)
- Optic Nerve Glioma (17)
- Optic Nerve Injuries (15)
- Optic Nerve Neoplasms (18)
- Optic Neuritis (130)
- Optic Neuropathy, Ischemic (44)
- Optic Pathway Glioma (42)
- Oral Cancer (462)
- Oral Hemorrhage (14)
- Oral Leukoplakia (30)
- Oral Manifestations (21)
- Oral Squamous Cell Carcinoma (49)
- Oral Submucous Fibrosis (9)
- Oral Ulcer (35)
- Orbital Cellulitis (3)
- Orbital Diseases (161)
- 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 (247)
- Orotic Aciduria Type 1 (1)
- Orthomyxoviridae Infections (1,739)
- Orthostatic Intolerance (232)
- Ossification of Posterior Longitudinal Ligament (5)
- Ossification, Heterotopic (30)
- Osteitis (34)
- Osteitis Deformans (15)
- Osteoarthritis (4,093)
- Osteoarthritis, Hip (443)
- Osteoarthritis, Knee (2,235)
- Osteoarthritis, Spine (12)
- Osteoarthropathy, Primary Hypertrophic (2)
- Osteoarthropathy, Secondary Hypertrophic (1)
- Osteoblastoma (1)
- Osteochondritis (30)
- Osteochondritis Dissecans (26)
- Osteochondrodysplasias (196)
- Osteochondroma (20)
- Osteochondromatosis (12)
- Osteochondrosis (29)
- Osteofibrous Dysplasia (1)
- Osteogenesis Imperfecta (54)
- Osteogenesis Imperfecta Type II (1)
- Osteogenesis Imperfecta Type III (9)
- Osteogenesis Imperfecta Type IV (1)
- Osteogenesis Imperfecta Type VI (3)
- Osteolysis (23)
- Osteolysis, Essential (3)
- Osteoma (7)
- Osteoma, Osteoid (7)
- Osteomalacia (40)
- Osteomyelitis (87)
- Osteonecrosis (142)
- Osteopetrosis (21)
- Osteopetrosis Autosomal Dominant Type 2 (1)
- Osteophyte (22)
- Osteoporosis (1,413)
- Osteoporosis, Postmenopausal (274)
- Osteoporosis-pseudoglioma Syndrome (2)
- Osteoporotic Fractures (77)
- Osteoradionecrosis (15)
- Osteosarcoma (541)
- Osteosarcoma, Juxtacortical (1)
- Osteosclerosis (25)
- Ostium Secundum Atrial Septal Defect (7)
- Otitis (312)
- Otitis Externa (25)
- Otitis Media (246)
- Otitis Media with Effusion (67)
- Otitis Media, Suppurative (9)
- Oto-Palatal-digital Syndrome (2)
- Oto-palato-digital Syndrome Type 1 (2)
- Otomycosis (8)
- Otorhinolaryngologic Diseases (4,815)
- Otorhinolaryngologic Neoplasms (939)
- Otosclerosis (12)
- Out-of-Hospital Cardiac Arrest (223)
- Ovarian Cancer (2,724)
- Ovarian Carcinosarcoma (28)
- Ovarian Cysts (639)
- Ovarian Diseases (2,632)
- Ovarian Epithelial Cancer (2,549)
- Ovarian Germ Cell Tumor (183)
- Ovarian Hyperstimulation Syndrome (69)
- Ovarian Low Malignant Potential Tumor (25)
- Ovarian Neoplasms (2,675)
- Ovarian Sex Cord Tumor With Annular Tubules (5)
- Ovarian Small Cell Carcinoma (3)
- Overbite (55)
- Overnutrition (3,711)
- Overweight (5,497)