diff --git a/src/Filtering/Filter.coffee b/src/Filtering/Filter.coffee
index 5c98a82fc..5a7eb4b33 100644
--- a/src/Filtering/Filter.coffee
+++ b/src/Filtering/Filter.coffee
@@ -150,7 +150,7 @@ Filter =
   tripcode:   (post) -> post.info.tripcode
   capcode:    (post) -> post.info.capcode
   pass:       (post) -> post.info.pass
-  subject:    (post) -> post.info.subject
+  subject:    (post) -> post.info.subject or (if post.isReply then undefined else '')
   comment:    (post) -> (post.info.comment ?= Build.parseComment post.info.commentHTML.innerHTML)
   flag:       (post) -> post.info.flag
   filename:   (post) -> post.file?.name