diff --git a/lib/html2text.php b/lib/html2text.php
index e2d0dffddbc..9cc213ddd60 100644
--- a/lib/html2text.php
+++ b/lib/html2text.php
@@ -335,7 +335,7 @@ class html2text
      */
     function html2text( $source = '', $from_file = false, $do_links = true, $width = 75 )
     {
-        if ( !empty($source) ) {
+        if ($source !== '') {
             $this->set_html($source, $from_file);
         }
 
diff --git a/lib/html2text_readme.txt b/lib/html2text_readme.txt
index 7fcaef1b3e7..7058045e5fc 100644
--- a/lib/html2text_readme.txt
+++ b/lib/html2text_readme.txt
@@ -53,3 +53,18 @@ Index: lib/html2text.php
  }
 
 -- Tim Hunt 2010-11-02
+
+4 - Make sure html2text does not destroy '0'.
+
+index e2d0dff..9cc213d 100644
+--- a/lib/html2text.php
++++ b/lib/html2text.php
+@@ -335,7 +335,7 @@ class html2text
+      */
+     function html2text( $source = '', $from_file = false, $do_links = true, $wi     {
+-        if ( !empty($source) ) {
++        if ($source !== '') {
+             $this->set_html($source, $from_file);
+         }
+
+-- Tim Hunt 2011-09-21
diff --git a/lib/simpletest/testweblib.php b/lib/simpletest/testweblib.php
index 20f6ebf73e1..0e7a39d3609 100644
--- a/lib/simpletest/testweblib.php
+++ b/lib/simpletest/testweblib.php
@@ -140,6 +140,10 @@ class web_test extends UnitTestCase {
         $this->assertEqual('With trailing whitespace and some more text', html_to_text("With trailing whitespace   \nand some   more text", 0));
     }
 
+    public function test_html_to_text_0() {
+        $this->assertIdentical('0', html_to_text('0'));
+    }
+
     public function test_clean_text() {
         $text = "lala <applet>xx</applet>";
         $this->assertEqual($text, clean_text($text, FORMAT_PLAIN));