diff --git array.c array.c
index 86cf09e..abe9555 100644
--- array.c
+++ array.c
@@ -3620,15 +3620,21 @@ rb_ary_plus(VALUE x, VALUE y)
 
 /*
  *  call-seq:
- *     ary.concat(other_ary)   -> ary
+ *     ary.concat(other_ary1, other_ary2,...)   -> ary
  *
- *  Appends the elements of +other_ary+ to +self+.
+ *  Appends the elements of +other_ary+s to +self+.
  *
  *     [ "a", "b" ].concat( ["c", "d"] ) #=> [ "a", "b", "c", "d" ]
+ *     [ "a" ].concat( ["b"], ["c", "d"] ) #=> [ "a", "b", "c", "d" ]
+ *     [ "a" ].concat #=> [ "a" ]
+ *
  *     a = [ 1, 2, 3 ]
  *     a.concat( [ 4, 5 ] )
  *     a                                 #=> [ 1, 2, 3, 4, 5 ]
  *
+ *     a = [ 1, 2 ]
+ *     a.concat(a, a)                    #=> [1, 2, 1, 2, 1, 2]
+ *
  *  See also Array#+.
  */
 
@@ -3643,6 +3649,15 @@ rb_ary_concat(VALUE x, VALUE y)
     return x;
 }
 
+static VALUE
+rb_ary_concat_m(int argc, VALUE *argv, VALUE ary)
+{
+	for (int i = 0; i < argc; i++)
+		rb_ary_concat(ary, argv[i]);
+
+	return ary;
+}
+
 
 /*
  *  call-seq:
@@ -5810,7 +5825,7 @@ Init_Array(void)
     rb_define_method(rb_cArray, "fetch", rb_ary_fetch, -1);
     rb_define_method(rb_cArray, "first", rb_ary_first, -1);
     rb_define_method(rb_cArray, "last", rb_ary_last, -1);
-    rb_define_method(rb_cArray, "concat", rb_ary_concat, 1);
+    rb_define_method(rb_cArray, "concat", rb_ary_concat_m, -1);
     rb_define_method(rb_cArray, "<<", rb_ary_push, 1);
     rb_define_method(rb_cArray, "push", rb_ary_push_m, -1);
     rb_define_method(rb_cArray, "pop", rb_ary_pop_m, -1);
diff --git string.c string.c
index 2782d28..4646670 100644
--- string.c
+++ string.c
@@ -2766,6 +2766,15 @@ rb_str_concat(VALUE str1, VALUE str2)
     return str1;
 }
 
+static VALUE
+rb_str_concat_m(int argc, VALUE *argv, VALUE ary)
+{
+	for (int i = 0; i < argc; i++)
+		rb_str_concat(ary, argv[i]);
+
+	return ary;
+}
+
 /*
  *  call-seq:
  *     str.prepend(other_str)  -> str
@@ -2786,6 +2795,15 @@ rb_str_prepend(VALUE str, VALUE str2)
     return str;
 }
 
+static VALUE
+rb_str_prepend_m(int argc, VALUE *argv, VALUE ary)
+{
+	for (int i = argc-1; i >= 0; i--)
+		rb_str_prepend(ary, argv[i]);
+
+	return ary;
+}
+
 st_index_t
 rb_str_hash(VALUE str)
 {
@@ -9681,9 +9699,9 @@ Init_String(void)
     rb_define_method(rb_cString, "codepoints", rb_str_codepoints, 0);
     rb_define_method(rb_cString, "reverse", rb_str_reverse, 0);
     rb_define_method(rb_cString, "reverse!", rb_str_reverse_bang, 0);
-    rb_define_method(rb_cString, "concat", rb_str_concat, 1);
+    rb_define_method(rb_cString, "concat", rb_str_concat_m, -1);
     rb_define_method(rb_cString, "<<", rb_str_concat, 1);
-    rb_define_method(rb_cString, "prepend", rb_str_prepend, 1);
+    rb_define_method(rb_cString, "prepend", rb_str_prepend_m, -1);
     rb_define_method(rb_cString, "crypt", rb_str_crypt, 1);
     rb_define_method(rb_cString, "intern", rb_str_intern, 0); /* in symbol.c */
     rb_define_method(rb_cString, "to_sym", rb_str_intern, 0); /* in symbol.c */