diff --git a/zerver/lib/bugdown/__init__.py b/zerver/lib/bugdown/__init__.py
index 4d9a5d1551..21b2b8b4f3 100644
--- a/zerver/lib/bugdown/__init__.py
+++ b/zerver/lib/bugdown/__init__.py
@@ -582,11 +582,11 @@ class AlertWordsNotificationProcessor(markdown.preprocessors.Preprocessor):
             # We check for a user's custom notifications here, as we want
             # to check for plaintext words that depend on the recipient.
             realm_words = alert_words.alert_words_in_realm(current_message.sender.realm)
+            content = '\n'.join(lines)
             for user, words in realm_words.iteritems():
                 for word in words:
                     escaped = re.escape(word)
                     match_re = re.compile(r'\b%s\b' % (escaped,))
-                    content = '\n'.join(lines)
                     if re.search(match_re, content):
                         current_message.user_ids_with_alert_words.add(user.id)