diff --git a/lib/isc/include/isc/mem.h b/lib/isc/include/isc/mem.h
index 58e1d0ee00..ed8b13398c 100644
--- a/lib/isc/include/isc/mem.h
+++ b/lib/isc/include/isc/mem.h
@@ -131,7 +131,7 @@ LIBISC_EXTERNAL_DATA extern unsigned int isc_mem_defaultflags;
 #if !ISC_MEM_USE_INTERNAL_MALLOC
 #define ISC_MEMFLAG_DEFAULT 0
 #else /* if !ISC_MEM_USE_INTERNAL_MALLOC */
-#define ISC_MEMFLAG_DEFAULT ISC_MEMFLAG_INTERNAL | ISC_MEMFLAG_FILL
+#define ISC_MEMFLAG_DEFAULT ISC_MEMFLAG_FILL
 #endif /* if !ISC_MEM_USE_INTERNAL_MALLOC */
 
 /*%