Aberdeen University has said it is committed to reducing animal testing in laboratories after criticism from campaigners.
Campaigners complained about injection of cannabis into rats
The move follows complaints by an anti-vivisection group that scientists injected rats with cannabis to examine how the drug affects memory.
A university spokesman confirmed the experiment was carried out in 2004.
However, he said staff were "striving to promote good practice" in laboratory animal welfare.
The spokesman added that all of the university's animal experiments had been carried out in accordance with strict Home Office controls.
He said: "The University of Aberdeen is committed to the reduction, replacement and refinement of animal testing.
"The use of animals is strictly controlled by the Home Office and the university strives to promote good practice in laboratory animal welfare and the development of non-animal replacement methods."
The experiments were said to have involved injecting the rats with cannabis and placing them into a container of non-harmful liquid, believed to be water.
Scientists then watched to see if the rodents could remember where a submerged platform was.
The BUAV claimed universities around the UK spend a total of £1m a year on experiments involving animals.
Its report was based on a review of papers on animal research into banned substances published in scientific journals since 1997.
The Creatures of Habit report by BUAV scientist Dr Katy Taylor claimed UK universities had repeatedly won licences from the Home Office to give often lethal doses of crystal meth, cocaine, cannabis, speed and ecstasy to animals.
Other institutes mentioned in the report include St Andrews, Dundee and Glasgow universities.
A spokesman for the BUAV said: "Aberdeen University has been caught red-handed abusing and harming animals in entirely pointless experiments."
Universities UK, which represents higher education institutions, defended the potential benefits of animal research.
A spokesman said: "Research on animals plays a significant role in advancing medical knowledge.
"UK regulation of animal research is among the tightest in the world and animal experimentation is only permitted where there are significant benefits for humans and animal health.
"Universities are becoming more open about the use of animal experimentation, which is an important step towards ensuring that there is a well informed and healthy debate about this issue."