SOP 10.5.3 - Euthanasia Method for Adult Rodents via Overdose of Inhalant Anaesthesia

University Animal Care Committee Standard Operating Procedure

Document No: 10.5.3

Subject: Euthanasia Method for Adult Rodents via Overdose of Inhalant Anaesthesia

Date Issued: August 21, 2012

Revision: 3

Location: Queen’s University

Responsibility: Principal Investigators (PI), Research Staff, Veterinary Staff

Purpose: The purpose of this Standard Operating Procedure (SOP) is to describe the procedure for the euthanasia of adult rodents using overdose of inhalant anaesthesia.

1. Introduction and Definitions:

As per the UACC policy on euthanasia of animals used in science, overdose of inhalant anesthesia is an acceptable method of euthanasia for adult rodents when conducted properly.


Animal Care Services ACS, Principal Investigator PI, subcutaneous SC, intravenous IV, intraperitoneal IP, intramuscular IM, per os PO, per rectum PR


2. Materials:

  • Calibrated inhalant isoflurane anaesthetic vaporizer with anaesthetic induction chamber
  • Oxygen
  • Instruments for secondary method (e.g. scissors, cage card holder)

3. Procedures:

  • Anesthetic chambers should not be overloaded and need to be kept clean to minimize odors that might distress the next animal euthanized.
  • The anesthetic can be introduced at a high concentration from a vaporizer of an anesthetic machine connected to an adequate scavenging system.
  • Sufficient room air or O2 must be provided during the induction period to prevent hypoxemia.
  • Neonatal animals (up to 10 days of age) are resistant to the hypoxia induced by high anesthetic gas concentrations, therefore, alternative methods are recommended. Inhalant anesthetics may be used for narcosis of neonatal animals provided it is followed by a secondary method of euthanasia (e.g. decapitation using sharp blades).
  • To confirm death, monitor animal for the following signs: no chest movement, no palpable heartbeat, poor mucous membrane color, no response to toe pinch, color change or opacity in eyes.

Note: A physical method of euthanasia such as cervical dislocation, bilateral pneumothorax, heart snip or exsanguination is required (unless otherwise justified in the animal use protocol) before disposal to ensure death.


Journal of the American Association for Laboratory Animal Science, Volume 45, Number 1, January 2006, pp. 98-105(8) James Artwohl, Patricia Brown, Brian Corning and Susan Stein Report of the ACLAM Task Force on Rodent Euthanasia

Date New Version
08/21/2012 Original SOP created
02/28/2019 Review and update
02/28/2022 Triennial review review
01/23/2023 Removed bell jar method, removed neonates and fetus’, updated format


SOP 10.5.3 - Euthanasia Method for Adult Rodents via Overdose of Inhalant Anaesthesia

Download SOP 10.5.3 (PDF 84 KB)