diff --git a/ChangeLog b/ChangeLog
index 194dff7ed1..d7af8540cf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+Sun Jun 28 23:32:11 2009  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* complex.c (nucomp_div): raises ZeroDivisionError immediately
+	  when the given second argument is zero.
+
+	* rational.c (nurat_fdiv): never raise even if the given second
+	  argument is zero.
+
+	* rational.c (rb_raise_zerodiv): changed the message (zero to 0).
+
 Sun Jun 28 22:25:07 2009  Tadayoshi Funaba  <tadf@dotrb.org>
 
 	* complex.c (nucomp_expt): convert to a float when the given power
diff --git a/complex.c b/complex.c
index 3863e685c3..5c2918e082 100644
--- a/complex.c
+++ b/complex.c
@@ -727,6 +727,8 @@ f_divide(VALUE self, VALUE other,
     return rb_num_coerce_bin(self, other, id);
 }
 
+#define rb_raise_zerodiv() rb_raise(rb_eZeroDivError, "divided by 0")
+
 /*
  * call-seq:
  *    cmp / numeric     ->  complex
@@ -742,6 +744,8 @@ f_divide(VALUE self, VALUE other,
 static VALUE
 nucomp_div(VALUE self, VALUE other)
 {
+    if (f_zero_p(other))
+	rb_raise_zerodiv();
     return f_divide(self, other, f_quo, id_quo);
 }
 
diff --git a/rational.c b/rational.c
index 8b28ac5ad1..8089f4a892 100644
--- a/rational.c
+++ b/rational.c
@@ -321,7 +321,7 @@ nurat_s_alloc(VALUE klass)
     return nurat_s_new_internal(klass, ZERO, ONE);
 }
 
-#define rb_raise_zerodiv() rb_raise(rb_eZeroDivError, "divided by zero")
+#define rb_raise_zerodiv() rb_raise(rb_eZeroDivError, "divided by 0")
 
 #if 0
 static VALUE
@@ -867,6 +867,8 @@ nurat_div(VALUE self, VALUE other)
 static VALUE
 nurat_fdiv(VALUE self, VALUE other)
 {
+    if (f_zero_p(other))
+	return f_div(self, f_to_f(other));
     return f_to_f(f_div(self, other));
 }