diff --git a/lisp/org.el b/lisp/org.el
index 3bf338d..c70d94d 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -3770,7 +3770,9 @@ characters, the face to be used by font-lock for highlighting in Org-mode
 Emacs buffers, and the HTML tags to be used for this.
 For LaTeX export, see the variable `org-export-latex-emphasis-alist'.
 For DocBook export, see the variable `org-export-docbook-emphasis-alist'.
-Use customize to modify this, or restart Emacs after changing it."
+The value of org-emphasis-alist is used to calculate a regular expression
+during startup; changing it manually may not have an effect.
+You should use customize to modify this. Otherwise, see `org-set-emph-re'."
   :group 'org-appearance
   :set 'org-set-emph-re
   :type '(repeat