The lists for the previous treatment field and the recommended treatment fields are very similar, so I rejigged the numeric values for some of the values in each of those fields, so that I ended up with no conflicts. This will ultimately allow me to use one "treatments" table should I want to, rather than two separate tables. Had to modify the GUI in the add.htm and doGetRecord.php files, the actual fields in the mysql db file and then I had to do a number of UPDATES the database to correct any records which had old values for any of the affected fields so that they now had the correct new values. Typical query (from memory): UPDATE exams SET previous_treatment_1 = 21 WHERE previous_treatment_1 = 18