diff --git a/includes/common.inc b/includes/common.inc
index 3b4bf58..8bec2c5 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -7419,7 +7419,7 @@ function drupal_explode_tags($tags) {
     // formatting so to save the term into the database as the user intends.
     $tag = trim(str_replace('""', '"', preg_replace('/^"(.*)"$/', '\1', $tag)));
     if ($tag != "") {
-      $tags[] = $tag;
+      $tags[] = str_replace('[--SLASH--]', '/', $tag);
     }
   }
 
diff --git a/misc/autocomplete.js b/misc/autocomplete.js
index 8f7ac60..275d0f3 100644
--- a/misc/autocomplete.js
+++ b/misc/autocomplete.js
@@ -293,7 +293,7 @@ Drupal.ACDB.prototype.search = function (searchString) {
     // encodeURIComponent to allow autocomplete search terms to contain slashes.
     $.ajax({
       type: 'GET',
-      url: db.uri + '/' + Drupal.encodePath(searchString),
+      url: db.uri + '/' + Drupal.encodePath(searchString).replace('%2F', '[--SLASH--]'),
       dataType: 'json',
       success: function (matches) {
         if (typeof matches.status == 'undefined' || matches.status != 0) {
diff --git a/modules/taxonomy/taxonomy.pages.inc b/modules/taxonomy/taxonomy.pages.inc
index 975ff12..b6b341f 100644
--- a/modules/taxonomy/taxonomy.pages.inc
+++ b/modules/taxonomy/taxonomy.pages.inc
@@ -119,13 +119,6 @@ function taxonomy_term_feed($term) {
  * @see taxonomy_field_widget_info()
  */
 function taxonomy_autocomplete($field_name = '', $tags_typed = '') {
-  // If the request has a '/' in the search text, then the menu system will have
-  // split it into multiple arguments, recover the intended $tags_typed.
-  $args = func_get_args();
-  // Shift off the $field_name argument.
-  array_shift($args);
-  $tags_typed = implode('/', $args);
-
   // Make sure the field exists and is a taxonomy field.
   if (!($field = field_info_field($field_name)) || $field['type'] !== 'taxonomy_term_reference') {
     // Error string. The JavaScript handler will realize this is not JSON and
diff --git a/modules/taxonomy/taxonomy.test b/modules/taxonomy/taxonomy.test
index 665f9ae..6073008 100644
--- a/modules/taxonomy/taxonomy.test
+++ b/modules/taxonomy/taxonomy.test
@@ -11,6 +11,14 @@
 class TaxonomyWebTestCase extends DrupalWebTestCase {
 
   /**
+   * Repeats the JS processing done to the input before sending it to the
+   * autocomplete URL.
+   */
+  function prepareAutocompleteInput($input) {
+    return str_replace('%2F', '[--SLASH--]', drupal_encode_path($input));
+  }
+
+  /**
    * Returns a new vocabulary with random properties.
    */
   function createVocabulary() {
@@ -751,7 +759,7 @@ class TaxonomyTermTestCase extends TaxonomyWebTestCase {
 
     // Try to autocomplete a term name that matches both terms.
     // We should get both term in a json encoded string.
-    $input = '10/';
+    $input = $this->prepareAutocompleteInput('10/');
     $path = 'taxonomy/autocomplete/taxonomy_';
     $path .= $this->vocabulary->machine_name . '/' . $input;
     // The result order is not guaranteed, so check each term separately.
@@ -763,7 +771,7 @@ class TaxonomyTermTestCase extends TaxonomyWebTestCase {
 
     // Try to autocomplete a term name that matches first term.
     // We should only get the first term in a json encoded string.
-    $input = '10/16';
+    $input = this->prepareAutocompleteInput('10/16');
     $url = 'taxonomy/autocomplete/taxonomy_';
     $url .= $this->vocabulary->machine_name . '/' . $input;
     $this->drupalGet($url);
@@ -771,7 +779,7 @@ class TaxonomyTermTestCase extends TaxonomyWebTestCase {
     $this->assertRaw(drupal_json_encode($target), 'Autocomplete returns only the expected matching term.');
 
     // Try to autocomplete a term name with both a comma and a slash.
-    $input = '"term with, comma and / a';
+    $input = this->prepareAutocompleteInput('"term with, comma and / a');
     $url = 'taxonomy/autocomplete/taxonomy_';
     $url .= $this->vocabulary->machine_name . '/' . $input;
     $this->drupalGet($url);