--- mbox.c	2006-02-07 19:27:06.000000000 +0100
+++ mbox.c	2007-07-27 02:14:52.000000000 +0200
@@ -224,7 +224,8 @@
 	else
 	  stringcopy (realfrom, reduce_from_(from_), sizeof(realfrom));
 
-	emit (prefix, realfrom, subject, priority, opt_flags);
+	if ( *realfrom || *subject )
+	  emit (prefix, realfrom, subject, priority, opt_flags);
 
 #ifdef FROM_DETECTION
 	from_[0] = from[0] = to[0] = subject[0] = '\0';