diff --git a/stdlib/Logging/docs/src/index.md b/stdlib/Logging/docs/src/index.md
index f5367d05b14a5..7a6fbbbdd2081 100644
--- a/stdlib/Logging/docs/src/index.md
+++ b/stdlib/Logging/docs/src/index.md
@@ -217,6 +217,9 @@ julia> foo()
 
 ```
 
+Use a comma separator to enable debug for multiple
+modules: `JULIA_DEBUG=loading,Main`.
+
 ## Examples
 
 ### Example: Writing log events to a file