Clinical Trials by Condition: O
- Obesity (9,832)
- Obesity Hypoventilation Syndrome (53)
- Obesity, Abdominal (225)
- Obesity, Maternal (44)
- Obesity, Metabolically Benign (14)
- Obesity, Morbid (749)
- Obsessive Behavior (2)
- Obsessive-Compulsive Disorder (463)
- Obstetric Labor Complications (2,423)
- Obstetric Labor, Premature (1,845)
- Occipital Horn Syndrome (2)
- Occupational Diseases (374)
- Occupational Injuries (10)
- Occupational Stress (200)
- Ochronosis (9)
- Ocular Cicatricial Pemphigoid (4)
- Ocular Hypertension (1,604)
- Ocular Hypotension (7)
- Ocular Melanoma (54)
- Ocular Motility Disorders (316)
- Ocular Muscular Dystrophy (6)
- Ocular Toxoplasmosis (4)
- Oculocerebral Syndrome With Hypopigmentation (4,508)
- Oculocerebrorenal Syndrome (6)
- Oculocutaneous Albinism (14)
- Oculomotor Nerve Diseases (4)
- Oculopharyngeal Muscular Dystrophy (12)
- Odontogenic Tumors (5)
- Ogilvie Syndrome (3)
- Olfaction Disorders (61)
- Olfactory Nerve Diseases (19)
- Olfactory Nerve Injuries (2)
- Olfactory Neuroblastoma (66)
- Oligoastrocytoma (97)
- Oligodendroglioma (376)
- Oligohydramnios (25)
- Oligomenorrhea (11)
- Oligospermia (33)
- Oliguria (12)
- Olivopontocerebellar Atrophies (2)
- Ollier Disease (8)
- Omenn Syndrome (6)
- Onchocerciasis (26)
- Onchocerciasis, Ocular (7)
- Oncogenic Osteomalacia (13)
- Onycholysis (5)
- Onychomycosis (122)
- Open Bite (11)
- Ophthalmia Neonatorum (2)
- Ophthalmoplegia (126)
- Ophthalmoplegia, Chronic Progressive External (10)
- Opiate Overdose (46)
- Opioid-Induced Constipation (96)
- Opioid-Related Disorders (990)
- 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 (356)
- Optic Nerve Glioma (17)
- Optic Nerve Hypoplasia (3)
- Optic Nerve Injuries (16)
- Optic Nerve Neoplasms (18)
- Optic Neuritis (138)
- Optic Neuropathy, Ischemic (45)
- Optic Pathway Glioma (42)
- Oral Cancer (499)
- Oral Hemorrhage (15)
- Oral Leukoplakia (31)
- Oral Manifestations (25)
- Oral Squamous Cell Carcinoma (173)
- Oral Submucous Fibrosis (9)
- Oral Ulcer (39)
- Orbital Cellulitis (3)
- Orbital Diseases (175)
- Orbital Fractures (15)
- Orbital Lymphoma (2)
- Orbital Neoplasms (8)
- Orbital Pseudotumor (4)
- Orchitis (3)
- Organic Acidemias (14)
- Organophosphate Poisoning (10)
- Ornithine Carbamoyltransferase Deficiency Disease (24)
- Ornithine Transcarbamylase Deficiency (24)
- Oroantral Fistula (2)
- Orofaciodigital Syndromes (2)
- Oropharyngeal Cancer, Adult (10)
- Oropharyngeal Neoplasms (261)
- Orotic Aciduria Type 1 (1)
- Orthomyxoviridae Infections (1,786)
- Orthostatic Intolerance (246)
- Ossification of Posterior Longitudinal Ligament (10)
- Ossification, Heterotopic (39)
- Osteitis (36)
- Osteitis Deformans (15)
- Osteoarthritis (4,337)
- Osteoarthritis, Hip (469)
- Osteoarthritis, Knee (2,401)
- Osteoarthritis, Spine (13)
- Osteoarthropathy, Primary Hypertrophic (2)
- Osteoarthropathy, Secondary Hypertrophic (1)
- Osteoblastoma (1)
- Osteochondritis (30)
- Osteochondritis Dissecans (26)
- Osteochondrodysplasias (202)
- 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 (24)
- Osteolysis, Essential (3)
- Osteoma (9)
- Osteoma, Osteoid (8)
- Osteomalacia (44)
- Osteomyelitis (92)
- Osteonecrosis (147)
- Osteopetrosis (21)
- Osteopetrosis Autosomal Dominant Type 2 (1)
- Osteophyte (24)
- Osteoporosis (1,450)
- Osteoporosis, Postmenopausal (289)
- Osteoporosis-pseudoglioma Syndrome (2)
- Osteoporotic Fractures (82)
- Osteoradionecrosis (17)
- Osteosarcoma (581)
- Osteosarcoma, Juxtacortical (1)
- Osteosclerosis (26)
- Ostium Secundum Atrial Septal Defect (7)
- Otitis (321)
- 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 (5,153)
- Otorhinolaryngologic Neoplasms (1,006)
- Otosclerosis (14)
- Ototoxicity (40)
- Out-of-Hospital Cardiac Arrest (241)
- Ovarian Cancer (2,850)
- Ovarian Carcinosarcoma (29)
- Ovarian Cysts (678)
- Ovarian Diseases (2,780)
- Ovarian Epithelial Cancer (2,668)
- Ovarian Germ Cell Tumor (185)
- Ovarian Hyperstimulation Syndrome (70)
- Ovarian Low Malignant Potential Tumor (25)
- Ovarian Neoplasms (2,801)
- Ovarian Sex Cord Tumor With Annular Tubules (5)
- Ovarian Small Cell Carcinoma (3)
- Ovarian Torsion (9)
- Overbite (63)
- Overnutrition (3,951)
- Overweight (5,838)