Animals are used in the development of new medical, veterinary and other products to work out whether or not the product does what it is supposed to do, and whether there are any side-effects. This may involve recreating a medical condition in the animal, such as diabetes or liver failure, to test whether the treatment can alleviate the symptoms. In the case of nutrition research, it may involve feeding different substances to animals with nutritional problems to see if they improve the animal’s condition. While many research techniques, such as cell-based studies, do not involve the use of live animals, there are still some areas where alternatives have not been identified and live animals continue to be used.

Animals are also used to test the safety of new products. These may be new drugs or other medical or veterinary treatments, or more general products such as washing powder, paint, or a new food additive. Safety testing is carried out because there are legal requirements that all substances that come into contact with humans or animals must be tested for their safety. This applies to any new substances or combinations of substances in medical and veterinary products, toiletries, and household products. In most cases this will involve some testing on animals, unless a non-animal alternative has been approved (which at the present time is unusual). If a company wants to market a new product it cannot be released unless these tests are carried out.