diff --git a/README.rst b/README.rst
index e76dcfd..23234f5 100644
--- a/README.rst
+++ b/README.rst
@@ -122,8 +122,10 @@ Djrill supports most of the functionality of Django's `EmailMessage`_ and
   raise a ``ValueError`` exception when you attempt to send the message.
   (Mandrill doesn't support sending multiple html alternative parts, or any
   non-html alternatives.)
-* Djrill attempts to include a message's attachments, though Mandrill may place
-  some restrictions on allowable attachment types. (See the Mandrill docs.)
+* Djrill attempts to include a message's attachments, but Mandrill will
+  (silently) ignore any attachment types it doesn't allow. According to
+  Mandrill's docs, attachments are only allowed with the mimetypes "text/*",
+  "image/*", or "application/pdf".
 * Djrill treats all cc and bcc recipients as if they were additional "to"
   addresses. (Mandrill does not distinguish cc, and only allows a single bcc --
   which Djrill doesn't use. *Caution:* depending on the ``preserve_recipients``