diff --git a/source/reference/method/db.auth-param.yaml b/source/reference/method/db.auth-param.yaml
index 354a355112a..4cccb8e510c 100644
--- a/source/reference/method/db.auth-param.yaml
+++ b/source/reference/method/db.auth-param.yaml
@@ -19,4 +19,13 @@ name: password
 type: string
 position: 2
 description: "Specifies the corresponding password."
+---
+field:
+  optional: true
+  type: param
+  default: MONGODB-CR
+name: mechanism
+type: string
+position: 3
+description: "Specifies the authentication mechanism used. Defaults to ``MONGODB-CR``. ``PLAIN`` is used for :doc:`SASL/LDAP authentication </tutorial/configure-ldap-sasl-openldap>`, available only in MongoDB Enterprise."
 ...
diff --git a/source/reference/method/db.auth.txt b/source/reference/method/db.auth.txt
index ced85f96761..60adab3f040 100644
--- a/source/reference/method/db.auth.txt
+++ b/source/reference/method/db.auth.txt
@@ -14,9 +14,13 @@ Definition
 
    .. include:: /reference/method/db.auth-param.rst
 
-   Alternatively, you can use :option:`mongo --username` and
-   :option:`--password <mongo --password>` to specify authentication
-   credentials.
+   Alternatively, you can use :option:`mongo --username`,
+   :option:`--password <mongo --password>`, and
+   :option:`--authenticationMechanism <mongo --authenticationMechanism>`
+   to specify authentication credentials.
+
+   :option:`--authenticationMechanism <mongo --authenticationMechanism>`
+   supports additional mechanisms not available when using :method:`db.auth()`.
 
    .. |operation-name| replace:: :method:`db.auth()`
    .. include:: /includes/note-auth-methods-excluded-from-shell-history.rst