We are developing an expert database system to assist NHLBI staff physicians in selecting and modifying drug treatment schedules for hypertensive patients. The methodology focuses on providing staff with rapid and concise information on current and proposed tests, procedures, and treatments. Such information is critical in designing efficient, cost-effective therapy plans which encourage long-term patient compliance. Initial computer programs built in dbase III+ to store and retrieve available pharmaceutical products, adverse reactions, drug-drug interactions have been converted to the Oracle relational database. Oracle allows random ad hoc queries to be entered in the powerful non-procedural SQL language. A Maclntosh PC with HyperCard's point and click button technology is the basis of a userfriendly human interface.