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The painful truth – shocking rise in pain experiments

A recent study has revealed a shocking increase in the amount of pain experiments conducted on mice in the past decade. 

Researchers from the Physicians Committee for Responsible Medicine in the USA conducted a literature review to document the trend in prolonged pain research, which is where animals are deliberately subjected to continuous pain for at least 14 days. Models of prolonged pain are created by cutting or crushing nerves, injecting substances that are known to cause inflammation and pain such as Freud’s Complete Adjuvant or inducing painful conditions such as arthritis and colitis. The animals may not be given any pain relief.

Disturbingly, they found that out of the last 40 years 63% of these experiments were conducted in recent years (i.e. since 2008). The UK was responsible for the fourth highest number of studies behind the USA, Japan and Germany. Out of a random selection of 55 of these experiments, not one mentioned the 3Rs or any of its components – Replace, Reduce or Refine – suggesting that pain researchers are indifferent to the 3Rs framework and that it is not considered a priority in the review process for publication in scientific journals. They also failed to find any evidence that the number of mice used per study is decreasing.

Not only are these experiments unimaginably cruel as animals are deliberately forced to suffer, but they are also unreliable. Ethical studies with human volunteers offer a much more powerful approach to pain research since- unlike animals- humans are able to verbally describe their experiences of pain and pain relief.



Prolonged pain research in mice: trends in reference to the 3Rs. (2013). Journal of Applied Animal Welfare Science, 16: 77-95.

Volunteer studies in pain research — Opportunities and challenges to replace animal experiments The report and recommendations of a Focus on Alternatives workshop. NeuroImage 42 (2008) 467–473