The animal experiment is central to the 3R concept. In European law, animal experiments are classed according to their aims. In the German animal protection law, they are classed, e.g. as interventions and treatments for experimental purposes, for further education and training, or for the production, preparation, storage or multiplication of substances, products or organisms and for the fulfillment of legal requirements, and are thus regulated with varying strictness. In contrast, in Switzerland all such measures performed on live animals underlie the same approval requirements. For animal welfarists, the term "animal experiment" includes every intervention and every treatment which is associated with pain, fear and/or suffering and does not directly benefit the respective animal. In the animal experiment, the animal concerned usually suffers as a human would, independent of the experimental goal. Expecting an animal to suffer a treatment one would not want to undergo oneself cannot be in accord with an ethic of respect for fellow creatures. Animal welfarists aim to save animals such suffering. Consequently, they demand the immediate abolition of all animal experiments. From the perspective of those who allow animal experiments to be performed or who perform them themselves, the goal of the experiment is more important than the animal. Therefore, the following question is central to 3R research: "Can I reach my goal while causing the animal less suffering, using fewer animals or without using animals at all?" The starting point is that the ethical responsibility for man is valued higher than that for the animal. The aim is to protect humans from harm caused by substances and products or from unwanted side effects of medication, to understand diseases and to search for a cure or alleviation of these. When a scientist reaches his goals without using animals, the demand of animal welfarists to abolish the animal experiment is fulfilled. These aspects do of course not encompass all the differences and agreements in the positions of animal welfarists and those who support animal experiments. It is not without reason that the discussion around animal experiments is multifaceted and continues to be held intensely from all positions. The classic pattern of a discussion entails that the one side collects the arguments which illustrate that animal experiments lead to wrong results, cannot be transferred and finally stand more against than for the good of mankind. The latter statement is valid, because the wrong methods benefit from investment, thus preventing or hindering new, better research and application of knowledge. The other side uses, among others, the argument that the person performing the experiment knows the limits of the test procedure and can deal with them accordingly. For further defense of current and future animal experiments, scientists like to present their organ transplant patients, i.e. those who can only lead a life worth living thanks to continuous medication, and admonish that patients with Alzheimer's or Parkinson's disease or with cancer put their last hope into new medical insights which can only be gained with animal experiments. Animal welfarists argue against this, that the motivation for animal experiments does not always lie in the ethical responsibility for mankind, but also in pure gain of knowledge, titles and money. After all, they also claim that they are protecting man, animal and environment from diseases and want to help them. It is not about saving animals at any price, even including human life, as is commonly brought against them. But they are also not prepared to accept that without real necessity or at any hint of a dilemma, the decision always falls immediately against the animal. The animal experiment may no longer be the method of choice, both for ethical and also for scientific reasons. What does all of this have to do with 3R research? It is a fact that animal experiments are still the method of choice, the "gold standard". The official German statistics on animal experiments in 2001 (Governmental animal protection report, 2002) counts a total of 2.13 mill. experimental animals, with a tendency towards a further increase. The increase is ascribed to animal experiments especially in basic research, counting 926,294 animals. The other more than a million animals were used for research and development of products and equipment for human, dental or veterinary medicine (509,101), the production or quality control of products or equipment for human, dental or veterinary medicine (289,273), toxicological investigations or other safety tests (189,996), the diagnosis of diseases (26,508), education and training (39,625) and other purposes (145,764). Before this background, all activities which lead away from animal experiments or reduce the suffering caused in the remaining experimental animals must be judged as positive developments. 3R research leads to a reduction of animal experiments and animal suffering. At the same time, the earnest consideration of the 3Rs also leads to a critical and specific discussion of the animal experiment in question.