# Cannabis irradiation

> Cannabis irradiation is treating harvested flower with ionising radiation, gamma, electron beam or X-ray, to cut microbial counts; permission and labelling rules vary.

- Canonical: https://genetixbay.com/knowledge/glossary/irradiation.html
- Also written: irradiation, irradiated cannabis, irradiated weed, gamma irradiation, e-beam treatment, x-ray treatment
- Glossary category: Legal and regulatory · Evidence: Supported
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

Cannabis irradiation is the use of ionising radiation to reduce bacteria, yeasts and moulds on harvested flower so it passes microbial limits. The main methods are gamma rays (usually from cobalt-60), electron beam (e-beam) and X-ray. Other decontamination methods include ozone, radio-frequency heating and UV, which are not ionising radiation. Irradiation does not make the flower radioactive.

## In practice

Some regulated markets allow irradiation of cannabis, and it is widely used in some medical supply chains; others restrict it. Whether it must be disclosed on the label varies, so consumers often cannot tell. Studies report modest changes: [cannabinoid](https://genetixbay.com/knowledge/glossary/cannabinoid.md) content largely unchanged, with some loss of [monoterpenes](https://genetixbay.com/knowledge/glossary/monoterpene.md) reported (Hazekamp 2016). Irradiation does not remove [mycotoxins](https://genetixbay.com/knowledge/glossary/mycotoxins.md) or pesticide residues already present, and it can mask poor drying or hygiene that caused the contamination.

GenetixBay's view: growing your own, where legal, is the surest way to know your flower was dried well rather than rescued by decontamination. [Prevention](https://genetixbay.com/knowledge/glossary/cultural-control.md) (clean rooms, airflow, a proper dry) beats a kill step.

Rules differ by country, state, province and city, and change often. This is a general definition, not legal advice: check local rules.

## Don't confuse with

- **UV treatment**: non-ionising, mainly surface-acting.
- **Pasteurisation**: heat-based, a different process.

## Related terms

[Compliance testing](https://genetixbay.com/knowledge/glossary/compliance-testing.md), [Labelling requirements](https://genetixbay.com/knowledge/glossary/labelling-requirements.md), [Licensed producer](https://genetixbay.com/knowledge/glossary/licensed-producer.md), [Terpene](https://genetixbay.com/knowledge/glossary/terpene.md), [Botrytis](https://genetixbay.com/knowledge/glossary/botrytis.md)

## Read more

- [Long-term storage: keeping cured flower potent and aromatic](https://genetixbay.com/knowledge/harvest-cure/long-term-storage.md)

## Sources

1. Hazekamp A. 2016. Evaluating the effects of gamma-irradiation for decontamination of medicinal cannabis. Frontiers in Pharmacology 7:108. https://doi.org/10.3389/fphar.2016.00108