diff --git a/docs/libcurl/opts/CURLOPT_RTSP_SESSION_ID.md b/docs/libcurl/opts/CURLOPT_RTSP_SESSION_ID.md
index e60438eecb..f7b41e4450 100644
--- a/docs/libcurl/opts/CURLOPT_RTSP_SESSION_ID.md
+++ b/docs/libcurl/opts/CURLOPT_RTSP_SESSION_ID.md
@@ -39,6 +39,9 @@ option.
 Using this option multiple times makes the last set string override the
 previous ones. Set it to NULL to disable its use again.
 
+**WARNING:** when changing the URL's origin in a reused easy handle, you might
+want to set or clear the Session ID to avoid reuse across different hosts.
+
 # DEFAULT
 
 NULL