Meta menu:

From here, you can access the Emergencies page, Contact Us page, Accessibility Settings, Language Selection, and Search page.

Open Menu
FAQ's auf dem Laptop Screen; Copyright Charité 3R; Foto: von Wardenburg


Why do scientists at the Charité conduct animal experiments? Why do they most often use mice for this purpose? And what legal regulations are animal experiments subject to?

You can find these and many more answers in our FAQ.

You are here:

Questions and answers about animal experiments

What is an animal experiment?

An animal experiment is the use of an animal to answer a scientific question that may lead to pain, suffering or harm. The use of an animal for the production, extraction, storage or reproduction of substances, for organ removal and for education, training or further training also counts as an animal experiment.

From a legal point of view, the German Animal Welfare Act defines the subject matter of "animal experimentation" somewhat differently than the overarching EU Directive. Although the differences only concern nuances, confusion and ambiguity can arise here when it comes to interpreting laboratory animal numbers, for example. One detail: According to German law, the harvesting of organs for scientific purposes also counts as animal experimentation (§7, paragraph (2) of the Animal Protection Act). The EU Directive 2010/63/EU, on the other hand, explicitly does not consider the killing of animals solely for the purpose of using their organs or tissues as animal experimentation (Article 3, 1). Against this background, information on the number of "animals not used in experiments that were killed" reported according to the EU Directive is somewhat ambiguous: it is not clear from the wording whether the figure in question includes animals that were killed for tissue removal. Depending on which definition of "animal experiment" one applies, both readings are possible.

Against this background, we use the most inclusive term possible for "animal experiment" on this website where there is no explicit reference to German law or EU regulation.

Why are animal experiments carried out?

For a number of diseases, there are still no adequate treatments. These include diseases of the cardiovascular system, diabetes, HIV, Alzheimer's and Parkinson's disease. Yet many issues are so complex that they cannot be investigated using animal-free methods. It is currently not possible to reconstruct a system with a beating heart, blood pressure and a functioning immune system in a cell culture or to simulate a heart attack with all its consequences on a computer. Animal experiments are needed because complex organisms such as the human body cannot yet be imitated in their entirety and there are a large number of complex processes and interactions that still need to be researched, especially in the area of disease development.

For the development and approval of medicinal products, animal experiments are also required by law for safety reasons to protect patients from clinical testing on humans. The efficacy, tolerability and quality of new medicines - just like those of other medical products - are strictly controlled. For the investigation of potential active substances in the pre-clinical phase, tests on at least two different animal species are even considered necessary.

All animal experiments at the Charité are planned and carried out in close cooperation with the Research Institutes for Experimental Medicine (FEM) and the animal welfare officers of the Charité. As the central institution of the Charité, the FEM are responsible for the breeding and keeping of the animals. With the function of the animal welfare officers, the legislator provides for a direct control authority in the respective facility, outside of the supervisory authority, to ensure compliance with the regulations, conditions and requirements in terms of the Animal Welfare Act on site. Within the scope of their powers, the animal protection officers have the possibility to prescribe measures or to suspend the implementation of animal experimentation projects with immediate effect. Furthermore, they advise scientists on the application and project implementation in terms of animal protection and form the bridge between the researchers at Charité and the responsible authority, the State Office for Health and Social Affairs (LASeSo).

What requirements must be met in order to be allowed to conduct animal experiments?

Animal experiments may only be carried out if they have been approved by the competent authorities - in Berlin the State Office for Health and Social Affairs (LAGeSo). In the application for approval, which is at least twelve pages long without being filled out, the scientist must provide comprehensive scientific and ethical justification for the planned experiment.

Among other things, it is important that the Animal Protection Act clearly defines permissible purposes to which a research question must be assigned. In the focus of the Charité, this concerns in particular the following purposes: basic research, the prevention, detection or treatment of diseases, suffering, bodily harm or physical complaints and the detection or influencing of physiological conditions or functions as well as the development of drugs. In addition, the indispensability of the experimental project must be demonstrated, i.e. what new knowledge will be gained with the animal experiment. In particular, it must be conclusively demonstrated that the objective of the project can only be achieved with an animal experiment. The ethical evaluation also includes proof that the experiment - in the sense of the 3Rs - cannot be replaced by alternative methods (replacement), that the number of animals is limited to an indispensable minimum (reduction), and that the stress on the animals is kept as low as possible (refinement).

Finally, the planned animal experiment must be described in detail, including the exact number of animals including statistical explanations and all planned interventions on the animals. In addition, certificates of competence and expertise of all persons involved in the animal experiment must be enclosed.
In addition to EU Directive 63/10/2010/EU, the Animal Welfare Act and the Animal Welfare Experimental Animal Ordinance, the Charité also has its own Charité Animal Welfare Guideline. The guideline is binding for all Charité employees who are involved in animal experimentation projects.

Further information on the legal basis can be found on the page

How does the regulatory review of an application for approval of an animal experiment proceed?

The approval authority checks whether an application is complete and the research project is comprehensible.

It is supported in this by an independent advisory commission, the Animal Experiments Commission (§15 TierSchG). At least one third of the commission members are appointed on the recommendation of animal protection organisations. The commission is also composed of expert veterinarians, physicians and scientists. All members perform this task on an honorary basis. They advise the licensing authority on the decision on an application by making a recommendation. For each animal experiment application, the authority also receives a statement from the animal welfare officers of the Charité. According to the law, the approval process should be completed within 40 days. If the authority concludes that all requirements are met, it approves the animal experiment. This can be done either without or with conditions (change in the number of animals or the choice of methods).

Further information on the approval procedure can be found on the pages of

Who bears the responsibility for an animal experiment?

In Berlin, the trial leader and his or her deputy are personally responsible for each individual approved project.

Who controls the keeping and handling of laboratory animals?

Due to the complex requirements of different animal species in terms of their husbandry, breeding and welfare, the husbandry and handling of laboratory animals is usually in the hands of a specialised "laboratory animal husbandry" unit, where appropriate specialist staff are employed.

At the Charité, these are the research facilities for experimental medicine (FEM). The specialised staff of the FEM includes animal keepers specialising in research and clinical work and veterinarians specialising in laboratory animal science. Anyone who wants to breed and keep animals for experimental purposes needs an official permit to do so. When applying for this permit, the legally required expertise of the staff in handling animals must be proven.

The competent authority also checks compliance with the legally prescribed framework conditions at regular intervals. These include room size, temperature, ventilation, noise pollution and lighting. On site, the keeping of laboratory animals is controlled by the animal welfare officers of the Charité, who also check the implementation of the approved animal experimentation projects. In the event of deviations in the husbandry or handling of the animals, the animal welfare officer has the possibility, within the scope of his or her powers, to prescribe measures or to suspend the implementation of animal experimentation projects with immediate effect.

What is the benefit of animal testing in clinical research?

In health care, most of the medical therapies and treatments used today, as well as many diagnostic procedures, have been developed with the help of animal experiments. Medical research has saved or improved the lives of countless people. The focus of a clinical research institution such as Charité-Universitätsmedizin is on the prevention, understanding and treatment of diseases, illnesses, bodily injuries or physical complaints in humans.

Clinically oriented basic research also has a wide range of animal models. A direct link to the benefit of the patient is not always easy to establish with basic research questions. In most cases, many partial findings only lead to an answer to a scientific question at a later stage. Translation, i.e. the transfer of research results to the clinic, is extensively regulated by the legislator for safety reasons. The safety of the procedures used in the clinic today for the patient has been ensured with the help of animal experiments.

The benefits of animal experiments therefore lie specifically in researching the causes of diseases and developing new treatment approaches, as well as in protecting patients from the risks of new types of therapy and treatment options.

Can findings from animal experiments be transferred to the human organism at all?

A look at the history of medicine proves how relevant research on animals is for humans. Many of the significant medical discoveries of the last 100 years can be directly traced back to animal experiments. Examples include antibiotics, insulin for diabetics, blood transfusions, to basic knowledge that bacteria can cause disease and the discovery of various viruses.

All vertebrates (mammals, birds, reptiles, amphibians and fish) are very similar because they are descended from common ancestors and thus their structure follows the same principles. They all have similar organs (heart, lungs, liver, etc.) that function very similarly and are controlled by the blood circulation and the nervous system. This similarity goes so far that one can even use different animal hormones to treat sick people in which they have the same effects (e.g. insulin from pigs and cows, calcitonin from salmon, oxytocin and vasopressin from pigs). Even animals that are only distantly related to us show many similarities. For example, human cells, just like those of insects, use the Hedgehog signalling pathway for communication during embryonic development. Deciphering this mechanism in fruit flies has led, among other things, to the development of the skin cancer drug vismodegib. Through basic research, we know which systems in which animals have a high degree of similarity to humans, so that a high degree of transferability can be assumed or proven here.

Differences between species can even be of particular interest, because transferability is not a prerequisite for relevance. If we better understand, for example, why the naked mole rat is resistant to cancer, or how the axolotl manages to simply regrow a severed leg or other tissue, this could lead to completely new therapies for humans. This research on animals thus contributes to a better understanding of the characteristics and peculiarities of animal species and in this way helps to further develop our ethical consideration and perception of animals.

Which animals are used for research at the Charité?

Scientists at the Charité conduct most of their research on mice and rats, as suitable, specifically genetically modified lines are available for most questions in both animal species. However, other species, e.g. fish such as the zebra danio (Danionella rerio) and the crystal danio (Danionella translucida) are also used in basic biomedical research and are becoming increasingly important as they are suitable for investigating diseases such as Alzheimer's or cancer. In contrast, sheep, pigs as well as guinea pigs and rabbits are more commonly used for research into cardiovascular diseases and bone healing, as the size ratios for e.g. implants are close to those of humans or bone healing is similar.

Which animal species a scientist uses depends on which model can be used to investigate a particular scientific question most precisely and which provides the best results that can be transferred to humans.

How is research done with animals at the Charité?

The biomedical research of different clinical disciplines is very diverse. Many laboratory animals are not used in a classical animal experiment, but are killed painlessly in order to obtain cells or tissue for further investigations. The proportion of such research has risen sharply in recent years, and this means that the animal, as a sensitive living being, does not have to experience pain, suffering or harm in an investigation or as a result of a treatment.

Clinical research is always about gaining a better understanding of how disease develops and improving therapy compared to current practice. The patient can benefit directly from this because of the proximity to the clinic.

With its many clinical disciplines, the Charité is also broadly positioned in terms of research and works in parallel on several research foci. One of these research focuses is neurodegenerative diseases. Genetically modified mouse lines exist for this as well, in which one or more genes have been altered. These are then used, for example, in behavioural tests to investigate how the animals behave in a new environment, how their learning ability is or whether there are changes in social behaviour.

How many animals currently live in the Charité's laboratory animal facilities?

Around 55.000 animals, mainly mice and rats, currently live in the laboratory animal farms. The demand for other animal species such as rabbits, guinea pigs, pigs and sheep was recently less than 0,5%. In addition, there are about 5.000 fish. 

What is the status of research into alternative methods?

The implementation of the 3Rs principle and thus also research into alternative methods have a very high priority, both in Germany and internationally. The 3Rs have now been anchored in various national and international codes as well as in laws, for example in the EU Directive 2010/63 on the protection of laboratory animals and in the German Animal Welfare Act. On this basis, national, international and supranational bodies have emerged with the aim of promoting the development of alternative methods and their recognition through legislation. At the national level, the Central Office for the Registration and Evaluation of Alternative and Complementary Methods to Animal Experiments (ZEBET) is an example of this, and at the European level, the European Centre for the Validation of Alternative Methods (ECVAM).

With the commitment to the Basel Declaration, which was also signed by the Charité, around 4.000 top scientists have now also committed themselves to acting in accordance with the highest ethical principles when conducting animal experiments. This includes, among other things - and as far as possible - the use of alternative methods.

In addition, the Federal Ministry of Education and Research (BMBF), the Federal Ministry of Food and Agriculture (BMEL) and the German Research Foundation (DFG), among others, support and promote the development of alternative methods. The individual federal states, research institutes and scientists themselves also have an interest in developing new alternative and complementary methods, as the founding of Charité 3R also shows.

What are transgenic animals?

DNA (deoxyribonucleic acid) contains the genetic information of an organism. It serves as a kind of "blueprint" for the various proteins that are produced in a cell and that essentially determine the cell's properties. The DNA section that codes for a specific protein is called a gene. Since the mid-1980s, conventional laboratory animals have been increasingly replaced in research by genetically modified animals. A transgenic animal, i.e. one that has been genetically modified, thus carries a modified piece of genetic information in the genome of all its body cells. Genetic changes can also result from mutations.

Using genetic engineering methods, for example, certain genes that trigger a disease in humans can be introduced into the genome of a mouse. This animal then shows a similar clinical picture to the human affected by the disease. It is also possible to remove or switch off a certain gene (knock-out).

Based on the changes, conclusions can be drawn about the mode of action of the genes that were switched off or introduced. Through research with transgenic animals, science is developing a deeper understanding of the causes of genetic diseases. This knowledge helps in the development of novel therapies. In knock-out mice, a specific genetic trait is specifically switched off in order to study the effects of this missing trait on the organism. In this way, for example, congenital immunodeficiency or metabolic diseases are researched, which often arise due to a defective or inactive gene.

What do stress levels mean?

The categories of stress levels and how experiments must be classified into these categories are defined in Directive 2010/63/EU of the European Parliament and of the Council of 22 September 2010 on the protection of animals used for scientific purposes. The exact definitions are given in the overview:

No recovery of vital function: procedures in which animals are killed for scientific purposes without pre-treatment or experiments carried out entirely under general anaesthesia from which the animal does not awaken are classified as 'no recovery of vital function'.

Low: Procedures that cause minor pain, suffering or distress to the animals for a short period of time and procedures that do not significantly affect the welfare or general condition of the animals are classified as "low".

Medium: Procedures causing short-term moderate pain, suffering or distress or prolonged mild pain to the animals and procedures causing moderate impairment of the welfare or general condition of the animals shall be classified as 'medium'.

Severe: Procedures causing severe pain, suffering or distress to the animals, or prolonged moderate pain, suffering or distress, and procedures causing severe impairment of the welfare or general condition of the animals shall be classified as 'severe'.