diff --git a/doc/configuration.txt b/doc/configuration.txt
index 073bb2f74..fe0669df9 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -1541,14 +1541,20 @@ expose-experimental-directives
   This statement must appear before using directives tagged as experimental or
   the config file will be rejected.
 
-external-check
+external-check [preserve-env]
   Allows the use of an external agent to perform health checks. This is
   disabled by default as a security precaution, and even when enabled, checks
   may still fail unless "insecure-fork-wanted" is enabled as well. If the
   program launched makes use of a setuid executable (it should really not),
   you may also need to set "insecure-setuid-wanted" in the global section.
-  See "option external-check", and "insecure-fork-wanted", and
-  "insecure-setuid-wanted".
+  By default, the checks start with a clean environment which only contains
+  variables defined in the "external-check" command in the backend section. It
+  may sometimes be desirable to preserve the environment though, for example
+  when complex scripts retrieve their extra paths or information there. This
+  can be done by appending the "preserve-env" keyword. In this case however it
+  is strongly advised not to run a setuid nor as a privileged user, as this
+  exposes the check program to potential attacks. See "option external-check",
+  and "insecure-fork-wanted", and "insecure-setuid-wanted" for extra details.
 
 fd-hard-limit <number>
   Sets an upper bound to the maximum number of file descriptors that the
diff --git a/include/haproxy/global-t.h b/include/haproxy/global-t.h
index f051832ae..e302de45d 100644
--- a/include/haproxy/global-t.h
+++ b/include/haproxy/global-t.h
@@ -105,7 +105,7 @@ struct proxy;
 struct global {
 	int uid;
 	int gid;
-	int external_check;
+	int external_check;             /* 0=disabled, 1=enabled, 2=enabled with env */
 	int nbthread;
 	int mode;
 	unsigned int hard_stop_after;	/* maximum time allowed to perform a soft-stop */
diff --git a/src/cfgparse-global.c b/src/cfgparse-global.c
index 7834ea18f..9e7e3324b 100644
--- a/src/cfgparse-global.c
+++ b/src/cfgparse-global.c
@@ -586,9 +586,16 @@ int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
 		}
 	}
 	else if (strcmp(args[0], "external-check") == 0) {
-		if (alertif_too_many_args(0, file, linenum, args, &err_code))
+		if (alertif_too_many_args(1, file, linenum, args, &err_code))
 			goto out;
 		global.external_check = 1;
+		if (strcmp(args[1], "preserve-env") == 0) {
+			global.external_check = 2;
+		} else {
+			ha_alert("parsing [%s:%d] : '%s' only supports 'preserve-env' as an argument, found '%s'.\n", file, linenum, args[0], args[1]);
+			err_code |= ERR_ALERT | ERR_FATAL;
+	                goto out;
+		}
 	}
 	/* user/group name handling */
 	else if (strcmp(args[0], "user") == 0) {
diff --git a/src/extcheck.c b/src/extcheck.c
index 0fd35a117..c667b1635 100644
--- a/src/extcheck.c
+++ b/src/extcheck.c
@@ -426,7 +426,10 @@ static int connect_proc_chk(struct task *t)
 				   (unsigned int)limit.rlim_cur, (unsigned int)limit.rlim_max);
 		}
 
-		environ = check->envp;
+		if (global.external_check < 2) {
+			/* fresh new env for each check */
+			environ = check->envp;
+		}
 
 		/* Update some environment variables and command args: curconn, server addr and server port */
 		EXTCHK_SETENV(check, EXTCHK_HAPROXY_SERVER_CURCONN, ultoa_r(s->cur_sess, buf, sizeof(buf)), fail);
@@ -445,6 +448,19 @@ static int connect_proc_chk(struct task *t)
 		EXTCHK_SETENV(check, EXTCHK_HAPROXY_SERVER_ADDR, check->argv[3], fail);
 		EXTCHK_SETENV(check, EXTCHK_HAPROXY_SERVER_PORT, check->argv[4], fail);
 
+		if (global.external_check >= 2) {
+			/* environment is preserved, let's merge new vars */
+			int i;
+
+			for (i = 0; check->envp[i] && *check->envp[i]; i++) {
+				char *delim = strchr(check->envp[i], '=');
+				if (!delim)
+					continue;
+				*(delim++) = 0;
+				if (setenv(check->envp[i], delim, 1) != 0)
+					goto fail;
+			}
+		}
 		haproxy_unblock_signals();
 		execvp(px->check_command, check->argv);
 		ha_alert("Failed to exec process for external health check: %s. Aborting.\n",