diff --git a/ChangeLog b/ChangeLog
index 62c16a36ee..163c38465f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Mar 18 12:48:01 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* error.c (report_bug): rb_bug can be caused by extension
+	  libraries.
+
 Wed Mar 18 02:41:33 2009  Masatoshi SEKI  <m_seki@mva.biglobe.ne.jp>
 
 	* lib/drb/drb.rb (open_server_inaddr_any): fixed multiple network
diff --git a/error.c b/error.c
index 95f98ca4dd..a5130471b0 100644
--- a/error.c
+++ b/error.c
@@ -216,7 +216,9 @@ report_bug(const char *file, int line, const char *fmt, va_list args)
 
 	fprintf(out,
 		"[NOTE]\n"
-		"You may have encountered a bug in the Ruby interpreter. Bug reports are welcome.\n"
+		"You may have encountered a bug in the Ruby interpreter"
+		" or extension libraries.\n"
+		"Bug reports are welcome.\n"
 		"For details: http://www.ruby-lang.org/bugreport.html\n\n");
     }
 }