use XML::RSS;
my $rss = new XML::RSS (version => '1.0', encoding => "UTF-8");
$rss->channel(title => "Test",
               link  => "http://example.com",
               description => "Test script",
               );
$rss->add_item(title => "Test",
                link  => "http://example.com/2",
                description => "<i>Some HTML</i> Some text",
                );
$rss->{output} = '1.0';
print $rss->as_string;

##</code><code>##

<?xml version="1.0" encoding="UTF-8"?>

<rdf:RDF
 xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 xmlns="http://purl.org/rss/1.0/"
 xmlns:taxo="http://purl.org/rss/1.0/modules/taxonomy/"
 xmlns:dc="http://purl.org/dc/elements/1.1/"
 xmlns:syn="http://purl.org/rss/1.0/modules/syndication/"
 xmlns:admin="http://webns.net/mvcb/"
>

<channel rdf:about="http://example.com">
<title>Test</title>
<link>http://example.com</link>
<description>Test script</description>
<items>
 <rdf:Seq>
  <rdf:li rdf:resource="http://example.com/2" />
 </rdf:Seq>
</items>
</channel>

<item rdf:about="http://example.com/2">
<title>Test</title>
<link>http://example.com/2</link>
<description>&lt;i>Some HTML&lt;/i> Some text</description>
</item>
</rdf:RDF>


##</code><code>##


<code>
<?xml version="1.0" encoding="UTF-8"?>

<rdf:RDF
 xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 xmlns="http://purl.org/rss/1.0/"
 xmlns:content="http://purl.org/rss/1.0/modules/content/"
 xmlns:taxo="http://purl.org/rss/1.0/modules/taxonomy/"
 xmlns:dc="http://purl.org/dc/elements/1.1/"
 xmlns:syn="http://purl.org/rss/1.0/modules/syndication/"
 xmlns:admin="http://webns.net/mvcb/"
>

<channel rdf:about="http://example.com">
<title>Test</title>
<link>http://example.com</link>
<description>Test script</description>
<items>
 <rdf:Seq>
  <rdf:li rdf:resource="http://example.com/2" />
 </rdf:Seq>
</items>
</channel>
<item rdf:about="http://example.com/2">
<title>Test</title>
<link>http://example.com/2</link>
<description>&#x3C;i&#x3E;Some HTML&#x3C;/i&#x3E; Some text</description>
</item>
</rdf:RDF>

##</code><code>##

<description>&lt;i>Some HTML&lt;/i> Some text</description>

vs

<description>&#x3C;i&#x3E;Some HTML&#x3C;/i&#x3E; Some text</description>