diff --git a/doc/guide.html b/doc/guide.html
index d4a8ef75f..a0f41f8a0 100644
--- a/doc/guide.html
+++ b/doc/guide.html
@@ -2477,6 +2477,10 @@ the room occupants.
{anonymous, true|false} The room is anonymous:
occupants don’t see the real JIDs of other occupants.
Note that the room moderators can always see the real JIDs of the occupants.
+{captcha_protected, false}
+When a user tries to join a room where he has no affiliation (not owner, admin or member),
+the room requires him to fill a CAPTCHA challenge (see section 3.1.8)
+in order to accept her join in the room.
{logging, false|true} The public messages are logged using mod_muc_log.
{max_users, 200} Maximum number of occupants in the room.
{members_by_default, true|false} The occupants that enter the room are participants by default, so they have ’voice’.
diff --git a/doc/guide.tex b/doc/guide.tex
index 272f933b4..ac5fc5527 100644
--- a/doc/guide.tex
+++ b/doc/guide.tex
@@ -3201,6 +3201,10 @@ Module options:
\titem{\{anonymous, true|false\}} The room is anonymous:
occupants don't see the real JIDs of other occupants.
Note that the room moderators can always see the real JIDs of the occupants.
+ \titem{\{captcha\_protected, false\}}
+ When a user tries to join a room where he has no affiliation (not owner, admin or member),
+ the room requires him to fill a CAPTCHA challenge (see section \ref{captcha})
+ in order to accept her join in the room.
\titem{\{logging, false|true\}} The public messages are logged using \term{mod\_muc\_log}.
\titem{\{max\_users, 200\}} Maximum number of occupants in the room.
\titem{\{members\_by\_default, true|false\}} The occupants that enter the room are participants by default, so they have 'voice'.