Neralie,
     >I was wondering whether there are any good alternatives to AEC as a
     >substrate for peroxidase when used in immunohistochemistry on 
     >paraffin sections.
     
     I've started using Vector's NovaRed chromogen in place of AEC and have 
     gotten satisfactory results. You get the red color with the advantage 
     that it can go through regular ethanol dehydration/clearing steps 
     without disappearing. 
     Best regards, 
     Rachel Stock HTL(ASCP)
     Organogenesis, Inc. 
     150 Dan Road
     Canton, MA 02021
     (781)575-0775