diff --git a/man/systemd.service.xml b/man/systemd.service.xml
index 0fe694ab7e..e26196323d 100644
--- a/man/systemd.service.xml
+++ b/man/systemd.service.xml
@@ -383,10 +383,21 @@
run, all processes remaining for a service are terminated
according to the KillMode= setting (see
systemd.kill5).
- If this option is not specified, the process is terminated
- immediately when service stop is requested. Specifier and
- environment variable substitution is supported (including
- $MAINPID, see above).
+ If this option is not specified, the process is terminated by
+ sending the signal specified in KillSignal=
+ when service stop is requested. Specifier and environment
+ variable substitution is supported (including
+ $MAINPID, see above).
+
+ Note that it is usually not sufficient to specify a
+ command for this setting that only asks the service to
+ terminate (for example by queuing some form of termination
+ signal for it), but does not wait for it to do so. Since the
+ remaining processes of the services are killed using
+ SIGKILL immediately after the command
+ exited this would not result in a clean stop. The specified
+ command should hence be a synchronous operation, not an
+ asynchronous one.