diff --git a/openerp/tools/mail.py b/openerp/tools/mail.py
index b825e3cffdb..92af711dc94 100644
--- a/openerp/tools/mail.py
+++ b/openerp/tools/mail.py
@@ -475,6 +475,10 @@ def html2plaintext(html, body_id=None, encoding='utf-8'):
     ## download here: http://www.peterbe.com/plog/html2plaintext
 
     html = ustr(html)
+
+    if not html:
+        return ''
+
     tree = etree.fromstring(html, parser=etree.HTMLParser())
 
     if body_id is not None: