diff --git a/plugins/disk/btrfs_device_stats b/plugins/disk/btrfs_device_stats
index 3f1b2e65..bd145024 100755
--- a/plugins/disk/btrfs_device_stats
+++ b/plugins/disk/btrfs_device_stats
@@ -16,6 +16,18 @@ Must be run as root.
 [btrfs_device_stats]
 user root
 
+You can optionaly configure the warning and critical limits. By default warning
+is set to 1 and critical is not set at all. You can set the limits either for
+the entire plugin or per individual metric. The individual values take
+precedence over the general ones. See the following example:
+
+[btrfs_device_stats]
+user root
+env.warning 2
+env.critical 4
+env.flags_warning 23
+env.read_errs_critical 42
+
 =head2 DEFAULT CONFIGURATION
 
 =head1 BUGS