diff --git a/src/syntax.c b/src/syntax.c
index 8d7f908865f..8aeb5bdd519 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -471,6 +471,7 @@ describe_syntax_1 (vector)
   struct buffer *old = current_buffer;
   set_buffer_internal (XBUFFER (Vstandard_output));
   describe_vector (vector, Qnil, describe_syntax, 0, Qnil);
+  call0 (intern ("help-mode"));
   set_buffer_internal (old);
   return Qnil;
 }