diff --git a/Documentation/MyFirstContribution.txt b/Documentation/MyFirstContribution.txt
index 7c9a037cc21..af0a9da62eb 100644
--- a/Documentation/MyFirstContribution.txt
+++ b/Documentation/MyFirstContribution.txt
@@ -664,7 +664,7 @@ mention the right animal somewhere:
 ----
 test_expect_success 'runs correctly with no args and good output' '
 	git psuh >actual &&
-	test_i18ngrep Pony actual
+	grep Pony actual
 '
 ----
 
diff --git a/config.c b/config.c
index 1137bd73aff..a8dec9a2479 100644
--- a/config.c
+++ b/config.c
@@ -996,15 +996,6 @@ static void die_bad_number(const char *name, const char *value)
 	if (!value)
 		value = "";
 
-	if (!strcmp(name, "GIT_TEST_GETTEXT_POISON"))
-		/*
-		 * We explicitly *don't* use _() here since it would
-		 * cause an infinite loop with _() needing to call
-		 * use_gettext_poison(). This is why marked up
-		 * translations with N_() above.
-		 */
-		die(bad_numeric, value, name, error_type);
-
 	if (!(cf && cf->name))
 		die(_(bad_numeric), value, name, _(error_type));
 
diff --git a/gettext.c b/gettext.c
index 35d2c1218db..308c4b31294 100644
--- a/gettext.c
+++ b/gettext.c
@@ -65,14 +65,6 @@ const char *get_preferred_languages(void)
 	return NULL;
 }
 
-int use_gettext_poison(void)
-{
-	static int poison_requested = -1;
-	if (poison_requested == -1)
-		poison_requested = git_env_bool("GIT_TEST_GETTEXT_POISON", 0);
-	return poison_requested;
-}
-
 #ifndef NO_GETTEXT
 static int test_vsnprintf(const char *fmt, ...)
 {
@@ -181,8 +173,6 @@ void git_setup_gettext(void)
 	if (!podir)
 		podir = p = system_path(GIT_LOCALE_PATH);
 
-	use_gettext_poison(); /* getenv() reentrancy paranoia */
-
 	if (!is_directory(podir)) {
 		free(p);
 		return;
diff --git a/gettext.h b/gettext.h
index bee52eb1134..c8b34fd6122 100644
--- a/gettext.h
+++ b/gettext.h
@@ -28,15 +28,12 @@
 
 #define FORMAT_PRESERVING(n) __attribute__((format_arg(n)))
 
-int use_gettext_poison(void);
-
 #ifndef NO_GETTEXT
 void git_setup_gettext(void);
 int gettext_width(const char *s);
 #else
 static inline void git_setup_gettext(void)
 {
-	use_gettext_poison(); /* getenv() reentrancy paranoia */
 }
 static inline int gettext_width(const char *s)
 {
@@ -48,14 +45,12 @@ static inline FORMAT_PRESERVING(1) const char *_(const char *msgid)
 {
 	if (!*msgid)
 		return "";
-	return use_gettext_poison() ? "# GETTEXT POISON #" : gettext(msgid);
+	return gettext(msgid);
 }
 
 static inline FORMAT_PRESERVING(1) FORMAT_PRESERVING(2)
 const char *Q_(const char *msgid, const char *plu, unsigned long n)
 {
-	if (use_gettext_poison())
-		return "# GETTEXT POISON #";
 	return ngettext(msgid, plu, n);
 }
 
diff --git a/git-sh-i18n.sh b/git-sh-i18n.sh
index 8eef60b43fd..e3d9f4836db 100644
--- a/git-sh-i18n.sh
+++ b/git-sh-i18n.sh
@@ -17,12 +17,7 @@ export TEXTDOMAINDIR
 
 # First decide what scheme to use...
 GIT_INTERNAL_GETTEXT_SH_SCHEME=fallthrough
-if test -n "$GIT_TEST_GETTEXT_POISON" &&
-	    git env--helper --type=bool --default=0 --exit-code \
-		GIT_TEST_GETTEXT_POISON
-then
-	GIT_INTERNAL_GETTEXT_SH_SCHEME=poison
-elif test -n "@@USE_GETTEXT_SCHEME@@"
+if test -n "@@USE_GETTEXT_SCHEME@@"
 then
 	GIT_INTERNAL_GETTEXT_SH_SCHEME="@@USE_GETTEXT_SCHEME@@"
 elif test -n "$GIT_INTERNAL_GETTEXT_TEST_FALLBACKS"
@@ -63,21 +58,6 @@ gettext_without_eval_gettext)
 		)
 	}
 	;;
-poison)
-	# Emit garbage so that tests that incorrectly rely on translatable
-	# strings will fail.
-	gettext () {
-		printf "%s" "# GETTEXT POISON #"
-	}
-
-	eval_gettext () {
-		printf "%s" "# GETTEXT POISON #"
-	}
-
-	eval_ngettext () {
-		printf "%s" "# GETTEXT POISON #"
-	}
-	;;
 *)
 	gettext () {
 		printf "%s" "$1"
diff --git a/po/README b/po/README
index 07595d369b0..efd5baaf1d8 100644
--- a/po/README
+++ b/po/README
@@ -284,23 +284,5 @@ Perl:
 Testing marked strings
 ----------------------
 
-Even if you've correctly marked porcelain strings for translation
-something in the test suite might still depend on the US English
-version of the strings, e.g. to grep some error message or other
-output.
-
-To smoke out issues like these, Git tested with a translation mode that
-emits gibberish on every call to gettext. To use it run the test suite
-with it, e.g.:
-
-    cd t && GIT_TEST_GETTEXT_POISON=true prove -j 9 ./t[0-9]*.sh
-
-If tests break with it you should inspect them manually and see if
-what you're translating is sane, i.e. that you're not translating
-plumbing output.
-
-If not you should replace calls to grep with test_i18ngrep, or
-test_cmp calls with test_i18ncmp. If that's not enough you can skip
-the whole test by making it depend on the C_LOCALE_OUTPUT
-prerequisite. See existing test files with this prerequisite for
-examples.
+Git's tests are run under LANG=C LC_ALL=C. So the tests do not need be
+changed to account for translations as they're added.
diff --git a/t/README b/t/README
index c730a707705..9a9dded033c 100644
--- a/t/README
+++ b/t/README
@@ -358,12 +358,6 @@ whether this mode is active, and e.g. skip some tests that are hard to
 refactor to deal with it. The "SYMLINKS" prerequisite is currently
 excluded as so much relies on it, but this might change in the future.
 
-GIT_TEST_GETTEXT_POISON=<boolean> turns all strings marked for
-translation into gibberish if true. Used for spotting those tests that
-need to be marked with a C_LOCALE_OUTPUT prerequisite when adding more
-strings for translation. See "Testing marked strings" in po/README for
-details.
-
 GIT_TEST_SPLIT_INDEX=<boolean> forces split-index mode on the whole
 test suite. Accept any boolean values that are accepted by git-config.
 
diff --git a/t/lib-gettext.sh b/t/lib-gettext.sh
index 2139b427ca1..cc6bb2cdeaa 100644
--- a/t/lib-gettext.sh
+++ b/t/lib-gettext.sh
@@ -17,7 +17,7 @@ else
 	. "$GIT_BUILD_DIR"/git-sh-i18n
 fi
 
-if test_have_prereq GETTEXT && test_have_prereq C_LOCALE_OUTPUT
+if test_have_prereq GETTEXT
 then
 	# is_IS.UTF-8 on Solaris and FreeBSD, is_IS.utf8 on Debian
 	is_IS_locale=$(locale -a 2>/dev/null |
diff --git a/t/lib-rebase.sh b/t/lib-rebase.sh
index b72c051f476..172d7459ff0 100644
--- a/t/lib-rebase.sh
+++ b/t/lib-rebase.sh
@@ -29,7 +29,6 @@ set_fake_editor () {
 	*/COMMIT_EDITMSG)
 		test -z "$EXPECT_HEADER_COUNT" ||
 			test "$EXPECT_HEADER_COUNT" = "$(sed -n '1s/^# This is a combination of \(.*\) commits\./\1/p' < "$1")" ||
-			test "# # GETTEXT POISON #" = "$(sed -n '1p' < "$1")" ||
 			exit
 		test -z "$FAKE_COMMIT_MESSAGE" || echo "$FAKE_COMMIT_MESSAGE" > "$1"
 		test -z "$FAKE_COMMIT_AMEND" || echo "$FAKE_COMMIT_AMEND" >> "$1"
diff --git a/t/t0017-env-helper.sh b/t/t0017-env-helper.sh
index c1ecf6aeac6..4a159f99e44 100755
--- a/t/t0017-env-helper.sh
+++ b/t/t0017-env-helper.sh
@@ -86,14 +86,14 @@ test_expect_success 'env--helper reads config thanks to trace2' '
 	git config -f home/cycle include.path .gitconfig &&
 
 	test_must_fail \
-		env HOME="$(pwd)/home" GIT_TEST_GETTEXT_POISON=false \
+		env HOME="$(pwd)/home" \
 		git config -l 2>err &&
 	grep "exceeded maximum include depth" err &&
 
 	test_must_fail \
-		env HOME="$(pwd)/home" GIT_TEST_GETTEXT_POISON=true \
-		git -C cycle env--helper --type=bool --default=0 --exit-code GIT_TEST_GETTEXT_POISON 2>err &&
-	grep "# GETTEXT POISON #" err
+		env HOME="$(pwd)/home" GIT_TEST_ENV_HELPER=true \
+		git -C cycle env--helper --type=bool --default=0 --exit-code GIT_TEST_ENV_HELPER 2>err &&
+	grep "exceeded maximum include depth" err
 '
 
 test_done
diff --git a/t/t0205-gettext-poison.sh b/t/t0205-gettext-poison.sh
deleted file mode 100755
index f9fa16ad836..00000000000
--- a/t/t0205-gettext-poison.sh
+++ /dev/null
@@ -1,39 +0,0 @@
-#!/bin/sh
-#
-# Copyright (c) 2010 Ævar Arnfjörð Bjarmason
-#
-
-test_description='Gettext Shell poison'
-
-GIT_TEST_GETTEXT_POISON=true
-export GIT_TEST_GETTEXT_POISON
-. ./lib-gettext.sh
-
-test_expect_success 'sanity: $GIT_INTERNAL_GETTEXT_SH_SCHEME" is poison' '
-    test "$GIT_INTERNAL_GETTEXT_SH_SCHEME" = "poison"
-'
-
-test_expect_success 'gettext: our gettext() fallback has poison semantics' '
-    printf "# GETTEXT POISON #" >expect &&
-    gettext "test" >actual &&
-    test_cmp expect actual &&
-    printf "# GETTEXT POISON #" >expect &&
-    gettext "test more words" >actual &&
-    test_cmp expect actual
-'
-
-test_expect_success 'eval_gettext: our eval_gettext() fallback has poison semantics' '
-    printf "# GETTEXT POISON #" >expect &&
-    eval_gettext "test" >actual &&
-    test_cmp expect actual &&
-    printf "# GETTEXT POISON #" >expect &&
-    eval_gettext "test more words" >actual &&
-    test_cmp expect actual
-'
-
-test_expect_success "gettext: invalid GIT_TEST_GETTEXT_POISON value doesn't infinitely loop" "
-	test_must_fail env GIT_TEST_GETTEXT_POISON=xyz git version 2>error &&
-	grep \"fatal: bad numeric config value 'xyz' for 'GIT_TEST_GETTEXT_POISON': invalid unit\" error
-"
-
-test_done
diff --git a/t/t3406-rebase-message.sh b/t/t3406-rebase-message.sh
index 4afc5281659..6340e9bc729 100755
--- a/t/t3406-rebase-message.sh
+++ b/t/t3406-rebase-message.sh
@@ -64,13 +64,6 @@ test_expect_success 'rebase -n overrides config rebase.stat config' '
 	! grep "^ fileX |  *1 +$" diffstat.txt
 '
 
-# Output to stderr:
-#
-#     "Does not point to a valid commit: invalid-ref"
-#
-# NEEDSWORK: This "grep" is fine in real non-C locales, but
-# GIT_TEST_GETTEXT_POISON poisons the refname along with the enclosing
-# error message.
 test_expect_success 'rebase --onto outputs the invalid ref' '
 	test_must_fail git rebase --onto invalid-ref HEAD HEAD 2>err &&
 	test_i18ngrep "invalid-ref" err
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 999982fe4a9..c7b1d857c46 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -988,19 +988,16 @@ test_cmp_bin () {
 	cmp "$@"
 }
 
-# Use this instead of test_cmp to compare files that contain expected and
-# actual output from git commands that can be translated.  When running
-# under GIT_TEST_GETTEXT_POISON this pretends that the command produced expected
-# results.
+# Wrapper for test_cmp which used to be used for
+# GIT_TEST_GETTEXT_POISON=false. Only here as a shim for other
+# in-flight changes. Should not be used and will be removed soon.
 test_i18ncmp () {
-	! test_have_prereq C_LOCALE_OUTPUT || test_cmp "$@"
+	test_cmp "$@"
 }
 
-# Use this instead of "grep expected-string actual" to see if the
-# output from a git command that can be translated either contains an
-# expected string, or does not contain an unwanted one.  When running
-# under GIT_TEST_GETTEXT_POISON this pretends that the command produced expected
-# results.
+# Wrapper for grep which used to be used for
+# GIT_TEST_GETTEXT_POISON=false. Only here as a shim for other
+# in-flight changes. Should not be used and will be removed soon.
 test_i18ngrep () {
 	eval "last_arg=\${$#}"
 
@@ -1013,12 +1010,6 @@ test_i18ngrep () {
 		BUG "too few parameters to test_i18ngrep"
 	fi
 
-	if test_have_prereq !C_LOCALE_OUTPUT
-	then
-		# pretend success
-		return 0
-	fi
-
 	if test "x!" = "x$1"
 	then
 		shift
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 9fa7c1d0f6d..c1ff5db2c17 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -404,15 +404,6 @@ TZ=UTC
 export LANG LC_ALL PAGER TZ
 EDITOR=:
 
-# GIT_TEST_GETTEXT_POISON should not influence git commands executed
-# during initialization of test-lib and the test repo. Back it up,
-# unset and then restore after initialization is finished.
-if test -n "$GIT_TEST_GETTEXT_POISON"
-then
-	GIT_TEST_GETTEXT_POISON_ORIG=$GIT_TEST_GETTEXT_POISON
-	unset GIT_TEST_GETTEXT_POISON
-fi
-
 # A call to "unset" with no arguments causes at least Solaris 10
 # /usr/xpg4/bin/sh and /bin/ksh to bail out.  So keep the unsets
 # deriving from the command substitution clustered with the other
@@ -1529,16 +1520,10 @@ test -n "$USE_LIBPCRE1" && test_set_prereq LIBPCRE1
 test -n "$USE_LIBPCRE2" && test_set_prereq LIBPCRE2
 test -z "$NO_GETTEXT" && test_set_prereq GETTEXT
 
-if test -n "$GIT_TEST_GETTEXT_POISON_ORIG"
-then
-	GIT_TEST_GETTEXT_POISON=$GIT_TEST_GETTEXT_POISON_ORIG
-	export GIT_TEST_GETTEXT_POISON
-	unset GIT_TEST_GETTEXT_POISON_ORIG
-fi
-
-test_lazy_prereq C_LOCALE_OUTPUT '
-	! test_bool_env GIT_TEST_GETTEXT_POISON false
-'
+# Used to be used for GIT_TEST_GETTEXT_POISON=false. Only here as a
+# shim for other in-flight changes. Should not be used and will be
+# removed soon.
+test_set_prereq C_LOCALE_OUTPUT
 
 if test -z "$GIT_TEST_CHECK_CACHE_TREE"
 then