diff --git a/doc/acrn.doxyfile b/doc/acrn.doxyfile
index e43a87da1..a0e16a596 100644
--- a/doc/acrn.doxyfile
+++ b/doc/acrn.doxyfile
@@ -866,7 +866,7 @@ EXCLUDE_PATTERNS       =
 # Exclude internal names (starting with an _) and doxygen-added __unnamed__
 # names given to unnamed nested unions
 
-EXCLUDE_SYMBOLS        = _*, *.__unnamed__
+EXCLUDE_SYMBOLS        = _* *.__unnamed__
 
 # The EXAMPLE_PATH tag can be used to specify one or more files or directories
 # that contain example code fragments that are included (see the \include