Excel's IF function certainly does TRUE/FALSE processing, and this can be combined with AND & OR functions, etc., as well as being nested. For example:

=IF(A1="milligrams",TRUE,FALSE)
=IF(A1="milligrams",B1,IF(A1="micrograms",B1*1000, 0))

If you want something more specific, you'll need to provide further details. It would also be helpful if you could attach a worksheet to a post with some representative data (delete anything sensitive). You do this via the paperclip symbol on the 'Go Advanced' tab at the bottom of this screen.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]