diff --git a/mercurial/patch.py b/mercurial/patch.py
index b576cce2af..9e5884032a 100644
--- a/mercurial/patch.py
+++ b/mercurial/patch.py
@@ -1010,7 +1010,7 @@ def filterpatch(ui, headers, operation=None):
             ui.write("\n")
             if r == 8: # ?
                 for c, t in ui.extractchoices(resps)[1]:
-                    ui.write('%s - %s\n' % (c, t.lower()))
+                    ui.write('%s - %s\n' % (c, encoding.lower(t)))
                 continue
             elif r == 0: # yes
                 ret = True
diff --git a/tests/test-commit-interactive.t b/tests/test-commit-interactive.t
index 3658b4c310..db44d85200 100644
--- a/tests/test-commit-interactive.t
+++ b/tests/test-commit-interactive.t
@@ -878,6 +878,32 @@ Help, quit
   abort: user quit
   [255]
 
+#if gettext
+
+Test translated help message
+
+str.lower() instead of encoding.lower(str) on translated message might
+make message meaningless, because some encoding uses 0x41(A) - 0x5a(Z)
+as the second or later byte of multi-byte character.
+
+For example, "\x8bL\x98^" (translation of "record" in ja_JP.cp932)
+contains 0x4c (L). str.lower() replaces 0x4c(L) by 0x6c(l) and this
+replacement makes message meaningless.
+
+This tests that translated help message is lower()-ed correctly.
+
+  $ LANGUAGE=ja
+  $ export LANGUAGE
+
+  $ hg commit -i --encoding cp932 2>&1 <<EOF | grep '^y - '
+  > ?
+  > q
+  > EOF
+  y - \x82\xb1\x82\xcc\x95\xcf\x8dX\x82\xf0\x8bL\x98^(yes) (esc)
+
+  $ LANGUAGE=
+#endif
+
 Skip
 
   $ hg commit -i <<EOF