diff --git a/postfix.grok b/postfix.grok
index d3996d4..11db0b4 100644
--- a/postfix.grok
+++ b/postfix.grok
@@ -12,7 +12,7 @@ POSTFIX_QUEUEID ([0-9A-F]{6,}|[0-9a-zA-Z]{12,}|NOQUEUE)
 POSTFIX_CLIENT %{HOSTNAME:postfix_client_hostname}?\[(%{IP_UNKNOWN:postfix_client_ip_unknown}|%{IP:postfix_client_ip})\](:%{INT:postfix_client_port})?
 POSTFIX_RELAY %{HOSTNAME:postfix_relay_hostname}?\[(%{IP:postfix_relay_ip}|%{DATA:postfix_relay_service})\](:%{INT:postfix_relay_port})?|%{WORD:postfix_relay_service}
 POSTFIX_SMTP_STAGE (CONNECT|HELO|EHLO|STARTTLS|AUTH|MAIL( FROM)?|RCPT( TO)?|(end of )?DATA|BDAT|RSET|UNKNOWN|END-OF-MESSAGE|VRFY|\.)
-POSTFIX_ACTION (accept|defer|discard|filter|header-redirect|reject|reject_warning)
+POSTFIX_ACTION (accept|defer|discard|filter|header-redirect|milter-reject|reject|reject_warning)
 POSTFIX_STATUS_CODE \d{3}
 POSTFIX_STATUS_CODE_ENHANCED \d\.\d+\.\d+
 POSTFIX_DNSBL_MESSAGE Service unavailable; .* \[%{GREEDYDATA:postfix_status_data}\] %{GREEDYDATA:postfix_status_message};
diff --git a/test/smtpd_0038.yaml b/test/smtpd_0038.yaml
new file mode 100644
index 0000000..4a91cf9
--- /dev/null
+++ b/test/smtpd_0038.yaml
@@ -0,0 +1,12 @@
+pattern: ^%{POSTFIX_SMTPD}$
+data: "NOQUEUE: milter-reject: RCPT from mailrelay.example.com[8.8.8.8]: 451 4.7.1 Greylisting in action, please come back later; from=<support@example.com> to=<example@example.org> proto=ESMTP helo=<mailrelay.example.com>"
+results:
+  postfix_queueid: NOQUEUE
+  postfix_status_code_enhanced: 4.7.1
+  postfix_keyvalue_data: from=<support@example.com> to=<example@example.org> proto=ESMTP helo=<mailrelay.example.com>
+  postfix_action: milter-reject
+  postfix_smtp_stage: RCPT
+  postfix_status_code: 451
+  postfix_client_ip: 8.8.8.8
+  postfix_status_message: "Greylisting in action, please come back later"
+  postfix_client_hostname: mailrelay.example.com