Animal health and welfare is an important area. When animals show signs of illness, some pet owners choose complementary and alternative veterinary medicine (KAVM) for their animals. Today, there is a lack of information about the clinical effect of the methods and why animal owners choose KAVM treatment. Increased knowledge about KAVM among animal owners, animal health personnel, insurance companies and authorities is therefore important. In this literature review our aim is to increase knowledge about the positive and negative effects of these methods.