diff --git a/morss/feeds.py b/morss/feeds.py
index 1be9b27..13cb760 100644
--- a/morss/feeds.py
+++ b/morss/feeds.py
@@ -319,7 +319,7 @@ class ParserXML(ParserBase):
         return self.root.getparent().remove(self.root)
 
     def tostring(self, encoding='unicode', **k):
-        return etree.tostring(self.root, encoding=encoding, **k)
+        return etree.tostring(self.root, encoding=encoding, method='xml', **k)
 
     def _rule_parse(self, rule):
         test = re.search(r'^(.*)/@([a-z]+)$', rule) # to match //div/a/@href
@@ -463,7 +463,7 @@ class ParserHTML(ParserXML):
         return html_parse(raw, encoding=self.encoding)
 
     def tostring(self, encoding='unicode', **k):
-        return lxml.html.tostring(self.root, encoding=encoding, **k)
+        return lxml.html.tostring(self.root, encoding=encoding, method='html', **k)
 
     def rule_search_all(self, rule):
         try:
@@ -724,7 +724,7 @@ class FeedXML(Feed, ParserXML):
         if self.root.getprevious() is None:
             self.root.addprevious(etree.PI('xml-stylesheet', 'type="text/xsl" href="/sheet.xsl"'))
 
-        return etree.tostring(self.root.getroottree(), encoding=encoding, **k)
+        return etree.tostring(self.root.getroottree(), encoding=encoding, method='xml', **k)
 
 
 class ItemXML(Item, ParserXML):
diff --git a/morss/morss.py b/morss/morss.py
index 2f00f3e..a3f072a 100644
--- a/morss/morss.py
+++ b/morss/morss.py
@@ -294,7 +294,7 @@ def ItemAfter(item, options):
         for link in content.xpath('//a'):
             log(link.text_content())
             link.drop_tag()
-        item.content = lxml.etree.tostring(content)
+        item.content = lxml.etree.tostring(content, method='html')
 
     if options.noref:
         item.link = ''
@@ -612,7 +612,7 @@ def cgi_get(environ, start_response):
                 for elem in html.xpath('//'+tag):
                     elem.getparent().remove(elem)
 
-            output = lxml.etree.tostring(html.getroottree(), encoding='utf-8')
+            output = lxml.etree.tostring(html.getroottree(), encoding='utf-8', method='html')
 
         elif options.get == 'article':
             output = readabilite.get_article(req['data'], url=req['url'], encoding_in=req['encoding'], encoding_out='utf-8', debug=options.debug)
diff --git a/morss/readabilite.py b/morss/readabilite.py
index 26bdc4c..0a945e0 100644
--- a/morss/readabilite.py
+++ b/morss/readabilite.py
@@ -341,7 +341,7 @@ def get_article(data, url=None, encoding_in=None, encoding_out='unicode', debug=
     if url:
         best.make_links_absolute(url)
 
-    return lxml.etree.tostring(best if not debug else html, pretty_print=True, encoding=encoding_out)
+    return lxml.etree.tostring(best if not debug else html, method='html', encoding=encoding_out)
 
 
 if __name__ == '__main__':