Clinical Trials by Condition: O
- Obesity (8,107)
- Obesity Hypoventilation Syndrome (41)
- Obesity, Abdominal (174)
- Obesity, Metabolically Benign (9)
- Obesity, Morbid (594)
- Obsessive Behavior (1)
- Obsessive-Compulsive Disorder (391)
- Obstetric Labor Complications (1,945)
- Obstetric Labor, Premature (1,489)
- Occipital Horn Syndrome (1)
- Occupational Diseases (231)
- Occupational Injuries (8)
- Occupational Stress (99)
- Ochronosis (5)
- Ocular Cicatricial Pemphigoid (4)
- Ocular Hypertension (1,363)
- Ocular Hypotension (6)
- Ocular Melanoma (51)
- Ocular Motility Disorders (235)
- Ocular Muscular Dystrophy (3)
- Ocular Toxoplasmosis (3)
- Oculocerebrorenal Syndrome (5)
- Oculocutaneous Albinism (13)
- Oculomotor Nerve Diseases (4)
- Oculopharyngeal Muscular Dystrophy (11)
- Odontogenic Tumors (4)
- Ogilvie Syndrome (1)
- Olfaction Disorders (12)
- Olfactory Nerve Injuries (1)
- Olfactory Neuroblastoma (62)
- Oligoastrocytoma (92)
- Oligodendroglioma (364)
- Oligohydramnios (19)
- Oligomenorrhea (7)
- Oligospermia (27)
- Oliguria (9)
- Olivopontocerebellar Atrophies (2)
- Omenn Syndrome (5)
- Onchocerciasis (22)
- Onchocerciasis, Ocular (6)
- Oncogenic Osteomalacia (11)
- Onycholysis (5)
- Onychomycosis (116)
- Open Bite (7)
- Ophthalmia Neonatorum (2)
- Ophthalmoplegia (89)
- Ophthalmoplegia, Chronic Progressive External (8)
- Opioid-Related Disorders (602)
- Opportunistic Infections (205)
- Opsoclonus-Myoclonus Syndrome (5)
- Optic Atrophies, Hereditary (36)
- Optic Atrophy (41)
- Optic Atrophy 1 (5)
- Optic Atrophy, Autosomal Dominant (5)
- Optic Atrophy, Hereditary, Leber (30)
- Optic Disk Drusen (2)
- Optic Nerve Diseases (286)
- Optic Nerve Glioma (16)
- Optic Nerve Injuries (13)
- Optic Nerve Neoplasms (17)
- Optic Neuritis (197)
- Optic Neuropathy, Ischemic (42)
- Optic Pathway Glioma (43)
- Oral Cancer (416)
- Oral Hemorrhage (10)
- Oral Leukoplakia (24)
- Oral Manifestations (18)
- Oral Squamous Cell Carcinoma (35)
- Oral Submucous Fibrosis (6)
- Oral Ulcer (29)
- Orbital Cellulitis (2)
- Orbital Diseases (138)
- Orbital Fractures (13)
- Orbital Lymphoma (1)
- Orbital Neoplasms (7)
- Orbital Pseudotumor (4)
- Orchitis (2)
- Organic Acidemia (7)
- Organophosphate Poisoning (9)
- Ornithine Carbamoyltransferase Deficiency Disease (15)
- Ornithine Transcarbamylase Deficiency (15)
- Orofaciodigital Syndromes (2)
- Oropharyngeal Cancer, Adult (9)
- Oropharyngeal Neoplasms (207)
- Orotic Aciduria Type 1 (1)
- Orthomyxoviridae Infections (1,625)
- Orthostatic Intolerance (202)
- Ossification of Posterior Longitudinal Ligament (4)
- Ossification, Heterotopic (28)
- Osteitis (27)
- Osteitis Deformans (15)
- Osteoarthritis (3,468)
- Osteoarthritis, Hip (356)
- Osteoarthritis, Knee (1,817)
- Osteoarthritis, Spine (10)
- Osteoarthropathy, Primary Hypertrophic (2)
- Osteoarthropathy, Secondary Hypertrophic (1)
- Osteoblastoma (1)
- Osteochondritis (25)
- Osteochondritis Dissecans (23)
- Osteochondrodysplasias (167)
- Osteochondroma (16)
- Osteochondromatosis (11)
- Osteochondrosis (24)
- Osteogenesis Imperfecta (45)
- Osteogenesis Imperfecta Type II (1)
- Osteogenesis Imperfecta Type III (8)
- Osteogenesis Imperfecta Type IV (1)
- Osteogenesis Imperfecta Type VI (3)
- Osteolysis (25)
- Osteolysis, Essential (3)
- Osteoma (6)
- Osteoma, Osteoid (6)
- Osteomalacia (37)
- Osteomyelitis (75)
- Osteonecrosis (128)
- Osteopetrosis (19)
- Osteopetrosis Autosomal Dominant Type 2 (1)
- Osteophyte (19)
- Osteoporosis (1,308)
- Osteoporosis, Postmenopausal (245)
- Osteoporosis-pseudoglioma Syndrome (2)
- Osteoporotic Fractures (68)
- Osteoradionecrosis (12)
- Osteosarcoma (473)
- Osteosarcoma, Juxtacortical (1)
- Osteosclerosis (21)
- Ostium Secundum Atrial Septal Defect (5)
- Otitis (283)
- Otitis Externa (24)
- Otitis Media (223)
- Otitis Media with Effusion (61)
- Otitis Media, Suppurative (8)
- Oto-Palatal-digital Syndrome (1)
- Oto-palato-digital Syndrome Type 1 (1)
- Otomycosis (6)
- Otorhinolaryngologic Diseases (4,138)
- Otorhinolaryngologic Neoplasms (796)
- Otosclerosis (12)
- Out-of-Hospital Cardiac Arrest (179)
- Ovarian Cancer (2,411)
- Ovarian Carcinosarcoma (26)
- Ovarian Cysts (574)
- Ovarian Diseases (2,396)
- Ovarian Epithelial Cancer (2,265)
- Ovarian Germ Cell Tumor (183)
- Ovarian Hyperstimulation Syndrome (68)
- Ovarian Low Malignant Potential Tumor (24)
- Ovarian Neoplasms (2,362)
- Ovarian Sex Cord Tumor With Annular Tubules (5)
- Ovarian Small Cell Carcinoma (2)
- Overbite (39)
- Overnutrition (3,167)
- Overweight (4,729)