diff --git a/README.md b/README.md
index de745209..49b2784b 100644
--- a/README.md
+++ b/README.md
@@ -5071,14 +5071,6 @@ Keep the right part of the string, after the index 'index'.
 
 Extract the medium string from offset 'index' and up to 'size' bytes.
 
-##### void string\_subset (string\_t v, const string\_t org, size\_t index, size\_t size)
-
-Extract the medium string from offset 'index' and up to 'size' bytes of 'org'
-and set it in 'v'.
-
-The subset string shall fully exist in the string org.
-The string 'v' and 'org' shall be different.
-
 ##### size\_t string\_replace\_str (string\_t v, const char str1[], const char str2[] [, size_t start])
 ##### size\_t string\_replace (string\_t v, const string\_t str1, const string\_t str2 [ , size_t start])
 
diff --git a/m-string.h b/m-string.h
index 267ac769..21976ebc 100644
--- a/m-string.h
+++ b/m-string.h
@@ -701,7 +701,9 @@ string_right(string_t v, size_t index)
   STRINGI_CONTRACT (v);
 }
 
-/* Return the string from position index to size bytes */
+/* Return the string from position index to size bytes.
+   See also string_set_n
+ */
 static inline void
 string_mid (string_t v, size_t index, size_t size)
 {
@@ -709,18 +711,6 @@ string_mid (string_t v, size_t index, size_t size)
   string_left(v, size);
 }
 
-/* Set the string 'v' to the substring of org from position index to size bytes */
-static inline void
-string_subset (string_t v, const string_t org, size_t index, size_t size)
-{
-  // The substring shall fully exist within the string org
-  assert(index + size <= string_size(org) );
-  assert(v != org);
-  
-  const char *str = string_get_cstr(org);
-  string_set_strn(v, &str[index], size);
-}
-
 /* Return in the string the C string str1 into the C string str2 from start
    By default, start is zero.
 */
diff --git a/tests/test-mstring.c b/tests/test-mstring.c
index ec4761c8..1643b24f 100644
--- a/tests/test-mstring.c
+++ b/tests/test-mstring.c
@@ -201,7 +201,7 @@ static void test0(void)
   string_mid (s1, j, 2);
   assert (string_cmp_str (s1, ", ") == 0);
 
-  string_subset (s1, s2, j, 2);
+  string_set_n (s1, s2, j, 2);
   assert (string_cmp_str (s1, ", ") == 0);
 
   string_set (s1, s2);