# ClinicalTrials.gov API

Category: [Health](https://free-web-services.com/web-services/open-data/health/)  
Page: https://free-web-services.com/web-services/open-data/health/clinicaltrials-gov-api.html  
Documentation: https://clinicaltrials.gov/data-api/api

The ClinicalTrials.gov API from the US National Library of Medicine searches more than 500,000 clinical studies from around the world, with their conditions, treatments, locations, status and results, for example to find recruiting trials for a disease near a city. Responses are JSON (or CSV), and an OpenAPI specification describes every field. Free, no key needed.

- API key: Not needed
- Pricing: Free, no key needed.
- From the browser: Yes (CORS)
- Formats: JSON
- Interface: REST, HTTP-GET
- Provider: clinicaltrials.gov
- Last checked: Working on November 7th, 2026

Example request:

```sh
curl 'https://clinicaltrials.gov/api/v2/studies?query.term=asthma&pageSize=1'
```

The JavaScript works in a web page as well as in Node.js 18 or newer.