A system generates medical knowledge base information by using predetermined data source specific message syntax information in identifying first and second information received from first and second data sources respectively. The first and second information indicates at least one type of medical relationship between the received first and second medical terms. The system determines likelihood of existence of the at least one type of medical relationship indicated by a combination of the first and second information, in response to predetermined information indicating a number of occurrences of the at least one type of relationship in data of at least one of the first and second data source. The system outputs first and second medical terms and the at least one type of medical relationship in response to the determined likelihood of existence.