According to Wikipedia, not everyone using the web for a medical search knows the right search keywords to use. To make it easier: 1st, it uses an interactive questionnaire-based query interface to guide users to provide the most important information about their situations. Users perform search by selecting symptoms and answering questions rather than by typing keyword queries. 2nd, it uses medical knowledge (e.g., diagnostic decision trees) to automatically form multiple queries from a user’ answers to the questions. These queries are used to perform search simultaneously. 3rd, it provides various kinds of help functions.