diff --git a/basis/smtp/smtp.factor b/basis/smtp/smtp.factor
index 83457defa5..61ccd5c435 100644
--- a/basis/smtp/smtp.factor
+++ b/basis/smtp/smtp.factor
@@ -187,7 +187,7 @@ ERROR: invalid-header-string string ;
         "<" %
         64 random-bits #
         "-" %
-        micros #
+        system-micros #
         "@" %
         smtp-domain get [ host-name ] unless* %
         ">" %