# UMLS Metathesaurus

License: restricted (LicenseRef-National-Library-of-Medicine-terms); Mdexa hosting: link-only. Second pass: derivatives: 第一遍自相矛盾：conditions 已列 no-derivatives，字段却写 unstated。类别 1 和类别 4 分别明示禁止翻译与制作衍生作品、禁止改动内容，类别 3 也把 creating derivative works 列为明确排除项，应改为 no。

- Commercial use: Unclear · Derivatives: No · Redistribution: Conditional · File on Mdexa: No
- License status: Restricted (LicenseRef-National-Library-of-Medicine-terms)
- Mdexa hosting: Link only — License restricted, judged by public rules and checked by a second-pass model. Link only.
- Last verified: 2026-11-13
- Card: https://mdexa.com/datasets/umls/

## Key facts

- Domain: Standards and terminology
- Content type: Terminologies and coding systems
- Size: —
- Language: English
- Modality: Text
- Publisher: National Library of Medicine
- Year: —

## Commercial use of UMLS Metathesaurus

- Commercial use: Unclear (Unstated).
The overall verdict takes the strictest part; the parts carry different licenses, listed below.
- License status: Restricted.
- Conditions: No derivatives
- License part: main data — Restricted (NOASSERTION)
- License part: UMLS vocabulary sources with additional restrictions (categories 1 to 4) — Restricted (NOASSERTION)
Verdicts record what sources state and are not legal advice.

## UMLS Metathesaurus license evidence

a restricted part cannot be separated or the boundary is unstated: strictest part applies

- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "The NLM hereby grants a nonexclusive, non-transferable right to LICENSEE to use the UMLS Metathesaurus and incorporate its content in any computer applications or systems designed to improve access to biomedical information of any type subject to the restrictions in other provisions of this Agreemen" — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "LICENSEE is prohibited from distributing the UMLS Metathesaurus or subsets of it, including individual vocabulary sources within the Metathesaurus, except (a) as an integral part of computer applications developed by LICENSEE for a purpose other than redistribution of vocabulary sources contained in" — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "For material in the UMLS Metathesaurus obtained from some sources additional restrictions on LICENSEE's use may apply." — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "LICENSEE is prohibited from translating the vocabulary source into another language or from producing other derivative works based on this single vocabulary source." — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "LICENSEE is prohibited from using the vocabulary source in operational applications that create records or information containing data from the vocabulary source." — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "LICENSEE's right to use material from the source vocabulary is restricted to internal use at the LICENSEE's site(s) for research, product development, and statistical analysis only." — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "LICENSEE is prohibited from translating the vocabulary source into another language or from altering the vocabulary source content." — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "LICENSEE has the right to distribute the vocabulary source in the U.S., but only in combination with other UMLS Metathesaurus content." — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "LICENSEE is prohibited from using the vocabulary source in operational applications that create records or information containing data from the vocabulary source. Use for data creation research or product development is allowed." — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "Internal research, product development, and statistical analysis use expressly excludes: use of material from these copyrighted sources in routine patient data creation; incorporation of material from these copyrighted sources in any publicly accessible computer-based information system or public el" — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "12.4.2. LICENSEE's right to use the vocabulary source is restricted to use in the U.S. by LICENSEE's employees, contractors, faculty, students, clients, patients, or constituents within electronic systems or devices built, purchased, licensed, or used by LICENSEE for U.S. governmental purposes or fo" — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)
- **Terms of use page**: Statement found in snapshot s01 (terms-page) — "12.4.1. LICENSEE is prohibited from translating the vocabulary source into another language or from altering the vocabulary source content." — https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html (2026-11-13; Page opened)

## Source and lineage

—

## Known issues with UMLS Metathesaurus

—

## Preflight

Not run (data not ingested).

## Downloading UMLS Metathesaurus and API access

Mdexa does not serve files. Original source:
- https://www.nlm.nih.gov/research/umls/
- https://www.nlm.nih.gov/research/umls/knowledge_sources/metathesaurus/release/license_agreement.html

## Citing UMLS Metathesaurus

No recommended citation text.

## Machine-readable

- JSON: https://mdexa.com/datasets/umls.json
- 2026-11-13 Listed on 2026-11-13. Judged by public rules and checked a second time before listing. The two passes disagreed; the stricter reading is carried: Second pass: derivatives: 第一遍自相矛盾：conditions 已列 no-derivatives，字段却写 unstated。类别 1 和类别 4 分别明示禁止翻译与制作衍生作品、禁止改动内容，类别 3 也把 creating derivative works 列为明确排除项，应改为 no。

## Continue in this database

This record is one of 109 processed and verified records (datasets, data resources and open models). To find others, call `https://mcp.mdexa.com/v1/datasets?q=<words>` or connect the MCP server at `https://mcp.mdexa.com/mcp`; no key is needed for 20 calls per minute. Rows are under 1 KB; an empty result means "not listed". For a list of items, one batch check (free account) returns a report. Guide: /agents.md. Similar records: ATC/DDD Index (https://mdexa.com/datasets/atc-ddd/); Human Phenotype Ontology (https://mdexa.com/datasets/hpo/); ICD-11 (https://mdexa.com/datasets/icd-11/).