An enormous proliferation of databases in almost all areas of human life has created great need to develop tools for automatic knowledge extraction. Extracted knowledge can be used for categorizing, organizing or predictive purposes. One of the problems encountered is how to make a good induction with good generalization and knowledge representation what is especial important in medical domain. Although the research filed is very active, it is mainly focused on a specific method or on a specific combination of those methods. In this paper a multimethod approach is presented. This approach unlike other conventional hybrid approaches applies different methods on the same knowledge base where each method may contain inherent limitations with the expectation that the combined multiple methods may produce better results. It also addresses unbalanced nature of medical data.