Medicines & Terminology

Learn ECL for
Healthcare Terminology

Master the SNOMED CT Expression Constraint Language (ECL) with our interactive query builder. Perfect for learners who want to understand how to query medicines, clinical findings, and other healthcare concepts.

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15+ Ready-to-Use Templates
Live Terminology Server
100% Free & Open Source
ECL Query 
<< 763158003 |Medicinal product| :
    127489000 |Has active ingredient| = 
        << 387517004 |Paracetamol|

Who Is This For?

ABC of ECL is designed for healthcare professionals working with clinical terminology

Clinical Informaticians

Build and test ECL queries for clinical decision support, value sets, and terminology bindings in your health IT systems.

Healthcare Developers

Learn ECL syntax to integrate SNOMED CT queries into your applications, APIs, and FHIR implementations.

Students & Learners

New to SNOMED CT? Start here to understand how ECL works through hands-on examples and instant feedback.

Explore the Site

Everything you need to learn and practice ECL

Query Builder

The heart of the application. Choose from 15+ templates, configure parameters, and execute ECL queries against a live terminology server. See results instantly and learn from the Query Anatomy breakdown.

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Examples

Browse practical ECL examples for common use cases like finding medications by ingredient, filtering by dose form, and querying clinical findings. Each example includes a "Try it" button.

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Resources

Links to official documentation, ECL operator reference, SNOMED CT browser, e-learning courses, and information about the terminology server powering this tool.

Browse Resources

Get Started in 3 Steps

From zero to running ECL queries in minutes

1

Learn the Basics

Understand what ECL is and why it matters. Read the "What is ECL?" section below to grasp the core concepts and operators.

Read Introduction
2

Try an Example

See ECL in action with real queries. Click "Try it" on any example to load it into the Query Builder and see the results.

Browse Examples
3

Build Your Own

Choose a template, configure your parameters, and execute. Use the Query Anatomy panel to understand every part of your query.

Open Query Builder

What is ECL?

Understanding Expression Constraint Language

Query Language

ECL is a formal syntax for representing SNOMED CT expression constraints. It allows you to define sets of clinical concepts using computable rules.

Hierarchical Navigation

Navigate the SNOMED CT hierarchy using operators like descendants (<), ancestors (>), and their inclusive variants (<<, >>).

Attribute Refinements

Refine your queries using attribute constraints to find concepts with specific properties like ingredients, dose forms, or clinical findings.

Medicines Focus

This tool focuses on querying medicines and pharmaceutical products, including VTMs, VMPs, AMPs, and packaged clinical drugs.

ECL Operators

ECL uses operators like << (descendants or self), : (refinement), and = (equals) to build powerful queries. See the full operator reference on the Resources page.

View Operator Reference

Ready to Start Learning?

Jump into the Query Builder to create your first ECL expression, or explore our examples to see ECL in action.

Query Builder View Examples Resources
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