diff --git a/ChangeLog b/ChangeLog
index af2ecc88cc..6d9446e53c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Feb 22 21:39:28 2011  Tanaka Akira  <akr@fsij.org>
+
+	* ext/openssl/ossl_digest.c: parenthesize macro arguments.
+
 Tue Feb 22 14:34:26 2011  Shota Fukumori (sora_h) <sorah@tubusu.net>
 
 	* lib/test/unit.rb: Fix merging miss.
diff --git a/ext/openssl/ossl_digest.c b/ext/openssl/ossl_digest.c
index 29d5371518..2b76fe7a49 100644
--- a/ext/openssl/ossl_digest.c
+++ b/ext/openssl/ossl_digest.c
@@ -11,14 +11,14 @@
 #include "ossl.h"
 
 #define GetDigest(obj, ctx) do { \
-    Data_Get_Struct(obj, EVP_MD_CTX, ctx); \
-    if (!ctx) { \
+    Data_Get_Struct((obj), EVP_MD_CTX, (ctx)); \
+    if (!(ctx)) { \
 	ossl_raise(rb_eRuntimeError, "Digest CTX wasn't initialized!"); \
     } \
 } while (0)
 #define SafeGetDigest(obj, ctx) do { \
-    OSSL_Check_Kind(obj, cDigest); \
-    GetDigest(obj, ctx); \
+    OSSL_Check_Kind((obj), cDigest); \
+    GetDigest((obj), (ctx)); \
 } while (0)
 
 /*