Browse All Conditions

Explore 28,964 medical conditions with active and completed U.S. clinical trial data drawn from ClinicalTrials.gov, the U.S. National Institutes of Health public registry. According to ClinicalTrials.gov, the National Institutes of Health public registry maintained by the U.S. National Library of Medicine catalogs more than 500,000 clinical studies across over 220 countries since 1997, with the U.S. Food and Drug Administration Amendments Act (FDAAA) of 2007 requiring registration for most studies of FDA-regulated products. See our methodology for refresh cadence.

PlainTrial's condition directory indexes every disease, disorder, syndrome, and medical condition with at least one clinical study registered on ClinicalTrials.gov. Each entry links to a per-condition profile page showing recruiting trials, completed studies, phase distribution, sponsor mix, and geographic coverage. We use the MeSH-aligned condition names submitted by trial sponsors to the National Library of Medicine, so a condition you find here is the same condition a clinician would search on PubMed or a researcher would tag in a grant application.

Use the alphabetical index to browse the full list, or sort by trial volume to find conditions with the deepest active research pipelines. Conditions with a "Recruiting" count in the third column have at least one trial currently enrolling participants - click through to see locations and eligibility. Conditions with high trial counts but zero recruiting slots usually reflect a maturing pipeline (Phase 3 studies are enrollment-closed) or a condition where standard-of-care has shifted research focus to combination therapies and post-approval surveillance.

The directory is comprehensive but not equally deep across conditions. Rare diseases may show fewer than a handful of trials because patient populations are limited - this is a feature of clinical research, not an indexing gap on our end. Common conditions (cancer subtypes, diabetes, hypertension, depression) show dozens to hundreds of studies because they attract the broadest sponsor investment. Every number on this page comes directly from ClinicalTrials.gov; we do not manually edit counts, and we update from the NLM bulk-export on a regular cadence so what you see reflects the most recent registry state we have ingested.

Breast Cancer1251Healthy1096Obesity1057Prostate Cancer749Depression687Cancer621HIV Infections615Hypertension472Stroke456Non-Small Cell Lung Cancer450
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Treemap Treemap of 10 categories, sized proportional to value. Breast Cancer - 1,251 Breast Cancer 1,251 Healthy - 1,096 Healthy 1,096 Obesity - 1,057 Obesity 1,057 Prostate Cancer - 749 Prostate Cancer 749 Depression - 687 Depression 687 Cancer - 621 Cancer 621 HIV Infections - 615 HIV Infections 615 Hypertension - 472 Hypertension 472 Stroke - 456 Stroke 456 Non-Small Cell Lung Cancer - 450 Non-Small Cell Lu… 450

28,964 conditions

Sort by: Name Most Trials Recruiting
Condition Trials
Primary Amenorrhea With Hypogonadotropic Hypogonadism 1
Primary Amyloidosis 2
Primary Amyloidosis of Light Chain Type 1
Primary Anatomic or Reverse Total Shoulder Arthroplasty 1
Primary Antibody Deficiencies 1
Primary Arthrosis 1
Primary Axillary Hyperhidrosis 1
Primary Bile Acid Diarrhea 1
Primary Biliary Cholangitis 9
Primary Biliary Cholangitis (PBC) 1
Primary Biliary Cirrhosis 8
Primary Body Region (Arranged Most Common to Least) 1
Primary Brain Neoplasm 3
Primary Brain Tumor 8
Primary Breast Augmentation 1
Primary Breast Reconstruction 1
Primary Cancer 2
Primary Care 6
Primary Care Appointment Keeping 1
Primary Care Patients With Chronic Conditions 1
Primary Central Nervous System (CNS) Lymphoma 1
Primary Central Nervous System Carcinoma 1
Primary Central Nervous System Lymphoma 13
Primary Central Nervous System Lymphoma (PCNSL) 6
Primary Central Nervous System Non-Hodgkin Lymphoma 1
Primary Cervical Dystonia 2
Primary Ciliary Dyskinesia 8
Primary Ciliary Dyskinesia (PCD) 1
Primary CNS Lymphoma 2
Primary CNS Tumors 1
Primary Cutaneous CD8+ Aggressive Epidermotropic T-Cell Lymphoma 1
Primary Cutaneous Diffuse Large B-Cell Lymphoma, Leg Type 1
Primary Cutaneous Gamma-Delta T-Cell Lymphoma 1
Primary Cutaneous T-cell Lymphoma 1
Primary Cutaneous T-Cell Non-Hodgkin Lymphoma 4
Primary Cutaneous Vasculitis 1
Primary Dental Caries, Multisurface Origin (Diagnosis) 1
Primary Diffuse Large B-Cell Lymphoma of the Central Nervous System 1
Primary Diffuse Large B-cell Lymphoma of the Central Nervous System (CNS) 1
Primary Disease 1
Primary Dysmenorrhea 3
Primary Dystonia 1
Primary Effusion Lymphoma 3
Primary Extra-cranial Solid Tumor 1
Primary Fibromyalgia 1
Primary Focal Segmental Glomerulosclerosis 1
Primary Generalized Epilepsy 1
Primary Generalized Tonic-Clonic Seizures 1
Primary Glioblastoma 1
Primary Glioblastoma Multiforme 1