hwg-guard

Regex backstop for German Heilmittelwerbegesetz (HWG) & EU Regulation 1924/2006 — flags medical claims, healing promises and unsafe health language in AI-generated marketing copy.

🇩🇪 Deutsche Version · 📖 Case Study

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Why this exists

You run an LLM (Claude, GPT, …) that writes marketing copy for food, supplements, cosmetics or "Hildegard von Bingen"-style traditional products. You tell it "don't write health claims" in the system prompt. It regresses anyway. One caption in fifty slips through something like:

"Dieser Tee heilt deine Erkältung in 3 Tagen."

In Germany that single sentence is a textbook § 3 HWG violation. The fine schedule goes up to €50k per incident, plus wettbewerbsrechtliche Abmahnungen from competitors.

This library is not a legal check — you still need a lawyer — but it catches the 80 % of common regressions before publish, at ~50 µs per caption, zero dependencies, one function call.

Install

npm install hwg-guard

Requires Node 18+. ESM only. TypeScript types included.

Usage

import { checkHWG } from 'hwg-guard';

const caption = "Dieser Tee hilft gegen Erkältung und stärkt dein Immunsystem.";

const result = checkHWG(caption);
// {
//   compliant: false,
//   flagged: [
//     { phrase: 'hilft gegen', reason: 'Wirkaussage' },
//     { phrase: 'gegen Erkältung', reason: 'Indikation' },
//     { phrase: 'stärkt',         reason: 'Staerkungs-Claim' },
//   ],
//   status: 'needs_legal_review',
// }

If result.compliant === true, publish. Otherwise route the content to a human reviewer.

n8n Code-Node drop-in

const { decorateForN8n } = require('hwg-guard');
return [{ json: decorateForN8n($input.first().json) }];

The decorator adds three fields — compliance_status, flagged_terms, status_for_db — so your SQL INSERT downstream can branch on status_for_db directly:

INSERT INTO content_queue (status, caption, ...)
VALUES ('{{ $json.status_for_db }}', '{{ $json.caption }}', ...);

Approved items auto-publish. Flagged items land in needs_legal_review and your Telegram/Slack approval-gate picks them up.

See examples/n8n-code-node.js for the full pattern.

CLI

echo "Hildegard von Bingen empfahl es gegen alle Leiden." \
  | node examples/cli-demo.js

Exit code is 0 when clean, 2 when flagged — useful for CI / pre-commit checks on static content.

What the 14 patterns catch

#	Pattern	Reason code	Covers
1	heilt	Heilversprechen	Direct healing promise
2	lindert	Wirkaussage	Symptom-relief claim
3	schützt vor	Praeventive Gesundheitsaussage	Preventive health claim
4	stärkt … (immun/abwehr/nerv/herz/körper)	Staerkungs-Claim	"Strengthens" + body system
5	hilft bei / hilft gegen	Wirkaussage	Indirect medical-purpose claim
6	gegen Erkältung / Demenz / Infekt / Grippe / …	Indikation	Disease-specific indication
7	optimiert	Funktions-Claim	"Optimizes" bodily function
8	reguliert	Funktions-Claim	"Regulates" bodily function
9	verbessert … (gesund/verdau/schlaf/konzentr)	Funktions-Claim	"Improves" + health area
10	schlaffördernd	Gesundheitsaussage	"Sleep-promoting"
11	verdauungsfreundlich	Gesundheitsaussage	"Digestion-friendly"
12	immunstärkend	Gesundheitsaussage	"Immune-strengthening"
13	Hildegard … (gegen/bei/hilft/heilt)	Tradition + Heilaussage	Hildegard-mysticism health exploit (DACH-common)
14	Krebs	Schwere Krankheit	Cancer — absolute prohibition per § 12 HWG

All patterns are case-insensitive (/i) and global (/g). They are a const array — you can import HWG_PATTERNS directly if you want to extend or override.

What this does NOT cover

• Nutrition claims under EU 1169/2011 (LMIV) — e.g. "zuckerfrei", "light"
• Pre-approved health claims you ARE allowed to make (see the EU Register)
• Comparative advertising (§ 6 UWG)
• Medical device regulation (MDR)
• Novel food disclosure (EU 2015/2283)
• Anything wrapped in sarcasm, metaphor or indirect framing that the regex doesn't literally match

Translation: if you publish regulated products in the DACH region, your lawyer is not optional.

Provenance

These patterns are extracted from the production newsletter-to-Instagram pipeline WRLZ.AI built for Tausendkraut — a DACH herbs brand. The full architecture, including the Claude prompt that sits in front of this guard, is documented in the case study:

→ https://wrlz.ai/case/tausendkraut/

Tests

npm test

12 unit tests, Node's built-in test runner, no dev dependencies.

License

MIT — use it, ship it, modify it. Includes an explicit liability disclaimer — regulatory compliance remains your responsibility.

Contributing

Found a regex that's too greedy / too loose? Open an issue with an example string and the German legal basis (HWG paragraph, EU regulation article, court decision). PRs welcome.

If you maintain a DACH regulated-products brand and hit a false positive that cost you a campaign slot, please tell us — real-world FP cases matter more than adding new patterns.

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Built by Pascal Jäger · pascal@wrlz.ai · Heidelberg