diff --git a/ChangeLog b/ChangeLog
index 05f70d8e5b..52db44d0f7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Mar  2 21:15:00 2011  Tanaka Akira  <akr@fsij.org>
+
+	* ext/openssl/ossl_pkey_dh.c: parenthesize macro arguments.
+
 Wed Mar  2 14:24:04 2011  Shota Fukumori  <sorah@tubusu.net>
 
 	* lib/test/unit/parallel.rb: Fix name from `inclement_io` to
diff --git a/ext/openssl/ossl_pkey_dh.c b/ext/openssl/ossl_pkey_dh.c
index 5ea575eaf9..4311fa1e96 100644
--- a/ext/openssl/ossl_pkey_dh.c
+++ b/ext/openssl/ossl_pkey_dh.c
@@ -13,8 +13,8 @@
 #include "ossl.h"
 
 #define GetPKeyDH(obj, pkey) do { \
-    GetPKey(obj, pkey); \
-    if (EVP_PKEY_type(pkey->type) != EVP_PKEY_DH) { /* PARANOIA? */ \
+    GetPKey((obj), (pkey)); \
+    if (EVP_PKEY_type((pkey)->type) != EVP_PKEY_DH) { /* PARANOIA? */ \
 	ossl_raise(rb_eRuntimeError, "THIS IS NOT A DH!") ; \
     } \
 } while (0)