diff --git a/ChangeLog b/ChangeLog
index c991f320ae..9947f00af3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Feb  1 20:45:44 2011  Tanaka Akira  <akr@fsij.org>
+
+	* enc/encdb.c: parenthesize macro arguments.
+
 Tue Feb  1 15:12:26 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* test/ruby/test_require.rb (TestRequire#test_require_with_unc):
diff --git a/enc/encdb.c b/enc/encdb.c
index 11f80e8640..958b33504e 100644
--- a/enc/encdb.c
+++ b/enc/encdb.c
@@ -14,11 +14,11 @@ int rb_encdb_alias(const char *alias, const char *orig);
 int rb_encdb_dummy(const char *name);
 void rb_encdb_declare(const char *name);
 void rb_enc_set_base(const char *name, const char *orig);
-#define ENC_REPLICATE(name, orig) rb_encdb_replicate(name, orig)
-#define ENC_ALIAS(name, orig) rb_encdb_alias(name, orig)
+#define ENC_REPLICATE(name, orig) rb_encdb_replicate((name), (orig))
+#define ENC_ALIAS(name, orig) rb_encdb_alias((name), (orig))
 #define ENC_DUMMY(name) rb_encdb_dummy(name)
 #define ENC_DEFINE(name) rb_encdb_declare(name)
-#define ENC_SET_BASE(name, orig) rb_enc_set_base(name, orig)
+#define ENC_SET_BASE(name, orig) rb_enc_set_base((name), (orig))
 
 void
 Init_encdb(void)