This information has been created in order to guide researchers and staff in the selection of most humane and appropriated method of euthanasia for the species that they are using.

Following the veterinarian and IACUC advice, the final decision of the method selected should be made by the principal investigator.

The euthanasia of animals used for scientific purpose is a very sensitive issue and It is our responsibility to ensure that it is done legally with the highest degree of respect, and with an emphasis on making the death as painless and distress free as possible.

Definition of terms

The term euthanasia is included in the Definition of Terms, 9 CFR Part 1 of the Animal Welfare regulations and is derived from Greek term “eu” meaning good and “thanatos” meaning a “good death” would be one that occurs with minimal pain and distress.

The Public Health Service (PHS) policy on Humane Care and Use of laboratory Animals states, “Method of euthanasia will be consistent with the recommendations of the American Veterinary Medical Association (AVMA) Panel on Euthanasia 2007, unless a deviation is justified for scientific reasons in writing by the investigator.”

Report of the American Veterinary Medical Association Panel on Euthanasia (AVMA), which is recognized by all regulatory agencies, is the accepted published guidelines for selecting and evaluating euthanasia techniques.

It is clearly describe in the Guidelines on Euthanasia by the AVMA, the animal and human behavioral considerations and mode of action of euthanazing agents.

The Guide for the Care and Use of Laboratory Animals is the basis for complying with the Public Health Science policy. The Guide defines euthanasia as: "the procedure of killing animals rapidly and painlessly"

Humane is defined as "Characterized by kindness, mercy, or compassion, marked by an emphasis on humanistic values and concerns. The central meaning shared by these adjective is "marked or motivated by concern with the alleviation of suffering"

Euthanasia is the act of inducing humane death in an animal.

Euthanasia techniques should result in rapid unconsciousness followed by cardiac or respiratory arrest and ultimate loss of brain function. In addition, the technique should minimize any stress and anxiety experienced by the animal prior to unconsciousness.

Proper technical skill and humane handling of the animals to be euthanazed may minimize stress.

When is it necessary euthanize an animal

Animals can be euthanized for various reasons, e.i. at the end of an experiment or when the level of pain of distress and suffering are likely to exceed the designated level.

The method chosen to euthanize animals, as part of the study should meet the following criteria:

Methods of Euthanasia

There are a variety of acceptable methods that can be used for each species. The advantage and disadvantage of each technique should be considered in selecting the most appropriate method for a particular project. Description of each method is given at the AVMA, Panel of Euthanasia, Appendix 1

Acceptable: Are those that consistently produce a humane death when used as sole means of euthanasia (Panel of Euthanasia, Appendix 2)
Conditionally acceptable: The AVMA Panel on Euthanasia states that, "conditionally acceptable methods are those techniques that by the nature of the technique or because of greater potential for operator error or safety hazards might not consistently produce humane death or are methods not well documented in the scientific literature." (Panel of Euthanasia, Appendix 3)
Unacceptable: These methods cannot be used on laboratory animals. The AVMA Panel on Euthanasia states that, "unacceptable techniques are those methods deemed inhumane under any conditions or that the panel found posed a substantial risk to the human applying the technique."
Unacceptable methods are considered inhumane and are absolutely condemned for use as euthanasia agents.
(Panel of Euthanasia, Appendix 4)
Adjunctive or Secondary Methods: Are methods that cannot be used as sole means of euthanasia, but can be used in conjunction with other methods to produce humane death
If primary method is: CO2 inhalation or
Inhalation anesthesia or
Injectable anesthesia
The secondary method used could be Exsanguination or
Decapitation or
Cervical dislocation or
bilateral pneumothorax


In addition to the selection of an appropriate method of euthanasia by the researcher, personnel engaged in the study must have training and be skilled in the proper handling of species involved including how to apply the euthanasia method used in a way to minimise stress in animals, and to recognize and confirm death in the species they are working with.

Aspects such as suitable method for each species, setting the location for perform euthanasia, disposal of carcasses function, maintance of equipment to be used, impact or stress in any form by those people observing or performing euthanasia and recognition of pain, distress in animals must be included in the training

All personnel that perform euthanasia should demonstrate professionalism and sensitivity for the value of animal life.

Prior to performing any method of euthanasia on the approved study, all scientist and staff must complete training provided by CARE.

Remember, the heart can still beat after breathing has stopped, so simply checking for the cessation of respiration is not adequate.

Proper Handling

Recognition and Confirmation of Death

Death must be confirmed after euthanasia and before disposal of the animal. Recognition of death may be made by cessation of heartbeat and respiration, absence of reflexes, including corneal and palpebral reflexes, loss of colour in mucous membranes, glazing of eyes and the lowering of the body temperature.

If any doubts transpire concerning the fact that death has occurred, a secondary euthanasia technique should be used to ensure the death of the animal.

Setting the location to perform euthanasia and Disposal of Carcasses

Animals should be euthanized in a clean quiet environment, away from other animals where possible. Death must be confirmed before disposal of the carcass and records should be kept.