diff --git a/cloud/rds b/cloud/rds
index cde7c5bcf20..14e888ecc86 100644
--- a/cloud/rds
+++ b/cloud/rds
@@ -125,7 +125,7 @@ options:
     aliases: []
   vpc_security_groups:
     description:
-      - Comma separated list of one or more vpc security groups. Used only when command=create or command=modify.
+      - Comma separated list of one or more vpc security group ids. Also requires `subnet` to be specified. Used only when command=create or command=modify.
     required: false
     default: null
     aliases: []