Among natives of various countries, a knowledge of medicine has been passed by word of mouth from one generation to the next by priests, witch doctors or medicine men. This is no less true in Ethiopia where written records in this field are almost absent even though the country has had a written language for over two thousand years. The method is crude and highly conducive to distortion in an area where much accuracy is needed. Some of the lore is lost at each point of transfer or otherwise modified and thereby becomes erroneous and dangerous to use. In addition, witch doctors, to safeguard their interests and win the respect of the inflicted masses, usually compose a long and impressive list of curative herbs for a particular disease when they know that it is only one of those listed that causes a cure. This is also done to fence out or discourage others from becoming herbal doctors if they are forced to tell the secret. For the same reasons, the plants comprising the remedy are selected from different ecological locations such as alpine, highlands, or lowlands; thus rendering it more difficult to accurately duplicate the ingredients. This means that even if one knew and had the list of the alleged curative herbs, he would not necessarily be able to become a practising witch doctor.