2026 data ClinicalTrials.gov official source

Conditions: O

Compiled by PlainTrial · January 1, 2026

Every condition beginning with O that has a registered US clinical trial, with how many studies cover each.

820 conditions starting with "O"

Showing 101–150 of 820

Condition	Trials	Recruiting
Occult Spina Bifida	1	1
Occupational Accidents	1	1
Occupational Burnout	1	-
Occupational Deprivation	1	-
Occupational Diseases	1	1
Occupational Exposure	2	1
Occupational Exposure to Chemicals	1	1
Occupational Exposure to SARS-CoV-2	1	-
Occupational Health	2	2
Occupational Injuries	1	1
Occupational Malignant Neoplasm	1	-
Occupational Problems	1	1
Occupational Stress	3	2
Occupational Therapy	5	3
OCD	19	13
OCS Lung System	1	-
OCT1	1	1
Octa	2	2
Ocular Blood Flow	1	-
Ocular Cicatricial Pemphigoid	2	-
Ocular Comfort	1	-
Ocular Complications	1	1
Ocular Conditions Resulting in Visual Impairment	1	-
Ocular Discomfort	2	-
Ocular Diseases	1	1
Ocular GVHD	1	1
Ocular Hypertension	57	12
Ocular Hypertension (OH)	3	2
Ocular Hypertension (OHT)	1	1
Ocular Hypertension Glaucoma	1	1
Ocular Images	1	-
Ocular Inflammation	3	1
Ocular Inflammation and Pain	1	-
Ocular Medulloepithelioma	1	1
Ocular Melanoma	5	3
Ocular Motility Disorders	1	-
Ocular Pain	2	-
Ocular Physiology	2	-
Ocular Rosacea	2	-
Ocular Surface Disease	3	1
Ocular Tumor	2	2
Oculo-Auriculo-Vertebral-Syndrome	1	-
Oculocutaneous Albinism	1	-
Oculofacial Reconstruction	1	1
Oculomotor Dysfunction	1	-
Oculopharyngeal Muscular Dystrophy	1	1
Odontalgia	2	1
Odontogenic Deep Space Neck Infection	1	-
Odontohypophosphatasia	1	1
Odor Identity Ratings	1	1

Data sourced from official public datasets. See our methodology for details.