diff --git a/process_request/routines.py b/process_request/routines.py
index 606bfec..a2eee56 100644
--- a/process_request/routines.py
+++ b/process_request/routines.py
@@ -21,6 +21,8 @@ class Processor(object):
 
     def strip_tags(self, user_string):
         """Strips XML and HTML tags from a string."""
+        if user_string is None:
+            return None
         try:
             xmldoc = ET.fromstring(f'<xml>{user_string}</xml>')
             textcontent = ''.join(xmldoc.itertext())