diff --git a/ChangeLog b/ChangeLog
index 65655e09ed..efb5c4f22d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Dec 19 14:59:30 2009  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* gem_prelude.rb (Kernel#gem): should make gem private.  a patch
+	  from Sho Hashimoto in [ruby-dev:39838].
+
 Sat Dec 19 14:57:17 2009  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* lib/webrick/config.rb (WEBrick::Config): typo fixed.  a patch
diff --git a/gem_prelude.rb b/gem_prelude.rb
index 5e12ac16a7..f83a341ff7 100644
--- a/gem_prelude.rb
+++ b/gem_prelude.rb
@@ -15,7 +15,7 @@ if defined?(Gem) then
     def gem(gem_name, *version_requirements)
       Gem.push_gem_version_on_load_path(gem_name, *version_requirements)
     end
-
+    private :gem
   end
 
   module Gem