You'd use an IF test for each option:
{IF{MERGEFIELD Eco}<> "#" "Eco: {MERGEFIELD Eco}"}{IF{MERGEFIELD Pol}<> "#" Pol: {MERGEFIELD Pol}{IF{MERGEFIELD Psy}<> "#" Psy: {MERGEFIELD Psy}

You can't use the AND test that way.

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