diff --git a/lisp/isearch.el b/lisp/isearch.el
index 336c5f1bde2..31fcf01949f 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -537,8 +537,6 @@ This is like `describe-bindings', but displays only Isearch keys."
     (describe-function 'isearch-forward))
   (when isearch-mode (isearch-update)))
 
-(defalias 'isearch-mode-help 'isearch-describe-mode)
-
 
 ;; Define isearch-mode keymap.
 
@@ -4636,6 +4634,8 @@ CASE-FOLD non-nil means the search was case-insensitive."
                        (replace-regexp-in-string "\"" "[\"“”]")))))
     (buffer-local-restore-state isearch-fold-quotes-mode--state)))
 
+(define-obsolete-function-alias 'isearch-mode-help #'isearch-describe-mode "29.1")
+
 (provide 'isearch)
 
 ;;; isearch.el ends here