Did the patent on librium expire?

Yes. The core patent covering Librium (chlordiazepoxide) has long expired in most markets, and the drug is now available as a generic in many countries.

Notes:
- There can still be active patents on specific formulations, salts, or new medical uses in some jurisdictions, but they don’t cover the basic molecule itself.
- Regulatory exclusivities (if any) for new indications or formulations can also affect market protection, even after the core patent expires.

If you want exact expiry dates by country or for a particular formulation, tell me the country and whether you mean the composition patent or a specific formulation, and I can guide you on where to look.