diff --git a/ietf/utils/mail.py b/ietf/utils/mail.py
index b86523fca..9e01ab835 100644
--- a/ietf/utils/mail.py
+++ b/ietf/utils/mail.py
@@ -302,7 +302,10 @@ def parse_preformatted(preformatted, extra={}, override={}):
     for k, v in override.iteritems():
          if k in msg:
               del msg[k]
-         msg[k] = v
+         if isinstance(v, list):
+              msg[k] = ', '.join(v)
+         else:
+              msg[k] = v 
 
     headers = copy.copy(msg)
     for key in ['To', 'From', 'Subject', 'Bcc']:
@@ -310,7 +313,10 @@ def parse_preformatted(preformatted, extra={}, override={}):
     for k, v in extra.iteritems():
          if k in headers:
               del headers[k]
-         headers[k] = v
+         if isinstance(v, list):
+              headers[k] = ', '.join(v)
+         else:
+             headers[k] = v 
 
     bcc = msg['Bcc']
     del msg['Bcc']
diff --git a/ietf/utils/tests.py b/ietf/utils/tests.py
index e440c652e..865856bec 100644
--- a/ietf/utils/tests.py
+++ b/ietf/utils/tests.py
@@ -29,7 +29,7 @@ import debug                            # pyflakes:ignore
 from ietf.group.models import Group
 from ietf.submit.tests import submission_file
 from ietf.utils.draft import Draft, getmeta
-from ietf.utils.mail import send_mail_text, send_mail_mime, outbox 
+from ietf.utils.mail import send_mail_preformatted, send_mail_text, send_mail_mime, outbox 
 from ietf.utils.management.commands import pyflakes
 from ietf.utils.test_data import make_test_data
 from ietf.utils.test_runner import get_template_paths, set_coverage_checking
@@ -54,6 +54,66 @@ class PyFlakesTestCase(TestCase):
         warnings = pyflakes.checkPaths([path], verbosity=0)
         self.assertEqual([], [str(w) for w in warnings])
 
+class SendingMail(TestCase):
+
+    def test_send_mail_preformatted(self):
+        msg = """To: to1@example.com, to2@example.com
+From: from1@example.com, from2@example.com
+Cc: cc1@example.com, cc2@example.com
+Bcc: bcc1@example.com, bcc2@example.com
+Subject: subject
+
+body
+"""
+        send_mail_preformatted(None, msg, {}, {})
+        recv = outbox[-1]
+        self.assertEqual(recv['To'], '<to1@example.com>, <to2@example.com>')
+        self.assertEqual(recv['From'], 'from1@example.com, from2@example.com')
+        self.assertEqual(recv['Cc'], 'cc1@example.com, cc2@example.com')
+        self.assertEqual(recv['Bcc'], None)
+        self.assertEqual(recv['Subject'], 'subject')
+        self.assertEqual(recv.get_payload(), 'body\n')
+
+        override = {
+            'To': 'oto1@example.net, oto2@example.net',
+            'From': 'ofrom1@example.net, ofrom2@example.net',
+            'Cc': 'occ1@example.net, occ2@example.net',
+            'Subject': 'osubject',
+        }
+        send_mail_preformatted(request=None, preformatted=msg, extra={}, override=override)
+        recv = outbox[-1]
+        self.assertEqual(recv['To'], '<oto1@example.net>, <oto2@example.net>')
+        self.assertEqual(recv['From'], 'ofrom1@example.net, ofrom2@example.net')
+        self.assertEqual(recv['Cc'], 'occ1@example.net, occ2@example.net')
+        self.assertEqual(recv['Bcc'], None)
+        self.assertEqual(recv['Subject'], 'osubject')
+        self.assertEqual(recv.get_payload(), 'body\n')
+
+        override = {
+            'To': ['<oto1@example.net>', 'oto2@example.net'],
+            'From': ['<ofrom1@example.net>', 'ofrom2@example.net'],
+            'Cc': ['<occ1@example.net>', 'occ2@example.net'],
+            'Subject': 'osubject',
+        }
+        send_mail_preformatted(request=None, preformatted=msg, extra={}, override=override)
+        recv = outbox[-1]
+        self.assertEqual(recv['To'], '<oto1@example.net>, <oto2@example.net>')
+        self.assertEqual(recv['From'], '<ofrom1@example.net>, ofrom2@example.net')
+        self.assertEqual(recv['Cc'], '<occ1@example.net>, occ2@example.net')
+        self.assertEqual(recv['Bcc'], None)
+        self.assertEqual(recv['Subject'], 'osubject')
+        self.assertEqual(recv.get_payload(), 'body\n')
+
+        extra = {'Fuzz': 'bucket'}
+        send_mail_preformatted(request=None, preformatted=msg, extra=extra, override={})
+        recv = outbox[-1]
+        self.assertEqual(recv['Fuzz'], 'bucket')
+
+        extra = {'Fuzz': ['bucket','monger']}
+        send_mail_preformatted(request=None, preformatted=msg, extra=extra, override={})
+        recv = outbox[-1]
+        self.assertEqual(recv['Fuzz'], 'bucket, monger')
+
 class TestSMTPServer(TestCase):
 
     def test_address_rejected(self):