GET studies

clinicaltrials.gov:clinicaltrials.gov-api

Summary: Search and retrieve clinical studies
Operation ID: searchStudies
Auth: none

Search and filter clinical trials based on various criteria including medical condition, intervention type, location, recruitment status, and more. Returns a paginated list of studies matching your criteria, with each study containing rich metadata including the NCT ID, title, status, conditions, interventions, sponsor information, and contact details. This is the primary endpoint for discovering clinical trials - use it when you need to find trials matching specific criteria (e.g., "all recruiting diabetes trials in California using metformin"). Results are paginated with a nextPageToken for retrieving additional pages. The response can be large (50KB+ per page) as it returns full study objects.

Original spec description

Returns a list of clinical studies matching the specified search criteria. Supports filtering by condition, term, sponsor, and other parameters. Results are paginated using a nextPageToken.

Usage Tips

- Use pageSize parameter (default 20, max 100) to control response size - Query parameters support AND logic - all conditions must match - Filter parameters (filter.overallStatus, filter.phase) work alongside query parameters - Search terms in query.term are matched across title, description, conditions, and interventions - Response does not include totalCount - use nextPageToken to iterate through results - For large result sets, consider adding date filters to narrow results

Parameters (15)

fields (string, query, optional)

Comma-separated list of fields to return (reduces payload size). Use module paths like NCTId, BriefTitle, Condition, Phase, OverallStatus.

filter.advanced (string, query, optional)

Advanced filter expression using boolean operators and field names

filter.overallStatus (string, query, optional)

Filter by overall study status

Constraints: {'enum': ['RECRUITING', 'NOT_YET_RECRUITING', 'ACTIVE_NOT_RECRUITING', 'COMPLETED', 'SUSPENDED', 'TERMINATED', 'WITHDRAWN', 'AVAILABLE', 'NO_LONGER_AVAILABLE', 'TEMPORARILY_NOT_AVAILABLE', 'APPROVED_FOR_MARKETING', 'WITHHELD', 'UNKNOWN']}

pageSize (integer, query, optional)

Number of studies to return per page (default varies, max 1000)

Constraints: {'minimum': 1, 'maximum': 1000}

pageToken (string, query, optional)

Token for retrieving the next page of results (from nextPageToken in previous response)

query.cond (string, query, optional)

Search by condition (e.g., cancer, diabetes, hypertension)

query.id (string, query, optional)

Search by NCT ID or other study identifier

query.intr (string, query, optional)

Search by intervention name

query.lead (string, query, optional)

Search by lead sponsor name

query.patient (string, query, optional)

Search by patient-specific criteria

query.spons (string, query, optional)

Search by sponsor name

query.term (string, query, optional)

General search term across study fields

query.titles (string, query, optional)

Search by study title

sort (string, query, optional)

Field to sort results by

Constraints: {'enum': ['NCTId', 'BriefTitle', 'Condition', 'OverallStatus', 'StartDate', 'CompletionDate', 'LastUpdatePostDate', 'StudyFirstPostDate']}

sortOrder (string, query, optional)

Sort order (ascending or descending)

Constraints: {'enum': ['asc', 'desc']}

Examples (6)

TitleTypeURLAction
Search clinical trials openapi-spec https://clinicaltrials.gov/api/v2/studies?query.term=heart disease&query.cond=diabetes&query.intr=metformin&query.locn=New York&query.spons=Harvard&filter.overallStatus=RECRUITING
Search trials by medical condition curl https://clinicaltrials.gov/api/v2/studies?query.cond=diabetes&pageSize=5
Search for recruiting cancer trials curl https://clinicaltrials.gov/api/v2/studies?query.cond=cancer&filter.overallStatus=RECRUITING&pageSize=10
Search by intervention and location curl https://clinicaltrials.gov/api/v2/studies?query.intr=vaccine&query.locn=United+States
Search clinical studies openapi-spec https://clinicaltrials.gov/api/v2/studies?query.cond=cancer&query.term=immunotherapy&query.locn=United States&query.intr=aspirin&query.id=NCT00281983&filter.overallStatus=RECRUITING&filter.phase=PHASE3
Search and retrieve clinical studies openapi-spec https://clinicaltrials.gov/api/v2/studies?query.cond=cancer&query.term=diabetes&query.intr=insulin&query.titles=cardiovascular&query.spons=National Cancer Institute&query.id=NCT01901835&filter.overallStatus=RECRUITING&filter.advanced=condition:cancer AND location:United States&fields=NCTId,BriefTitle,Condition,OverallStatus&pageSize=10&sortOrder=desc

Probe History

Latency

Status Codes

TimeStatusLatencySize
2026-03-23 10:45:12.876608 400 173ms
2026-03-23 10:32:43.982934 400 170ms
2026-03-23 10:23:05.597363 200 172ms
2026-03-23 09:19:14.827651 200 199ms
2026-03-23 09:14:41.407399 200 173ms
2026-03-23 09:07:38.149480 200 194ms

Response Changes

WhenOldNew
2026-03-23 09:14:41.407399 e5660ca1fb1b b31af9871caa
2026-03-23 09:19:14.827651 b31af9871caa 9332558065c5
2026-03-23 10:23:05.597363 9332558065c5 ff0033a38631
2026-03-23 10:32:43.982934 ff0033a38631 eed9d1950946
2026-03-23 10:45:12.876608 eed9d1950946 643cd7a890f6