diff --git a/tabulate/__init__.py b/tabulate/__init__.py
index 12a2950..7bbd2bb 100644
--- a/tabulate/__init__.py
+++ b/tabulate/__init__.py
@@ -193,10 +193,16 @@ def _mediawiki_row_with_attrs(separator, cell_values, colwidths, colaligns):
     return (separator + colsep.join(values_with_attrs)).rstrip()
 
 
+def _escape_pipe(value):
+    return value.replace("|", "|")
+
+
 def _textile_row_with_attrs(cell_values, colwidths, colaligns):
     cell_values[0] += " "
     alignment = {"left": "<.", "right": ">.", "center": "=.", "decimal": ">."}
-    values = "|".join(alignment.get(a, "") + v for a, v in zip(colaligns, cell_values))
+    values = "|".join(
+        alignment.get(a, "") + _escape_pipe(v) for a, v in zip(colaligns, cell_values)
+    )
     return f"|{values}|"
 
 
@@ -236,7 +242,11 @@ def _moin_row_with_attrs(celltag, cell_values, colwidths, colaligns, header=""):
         "decimal": '<style="text-align: right;">',
     }
     values_with_attrs = [
-        "{}{} {} ".format(celltag, alignment.get(a, ""), header + c + header)
+        "{}{} {} ".format(
+            celltag,
+            alignment.get(a, ""),
+            header + _escape_pipe(c) + header,
+        )
         for c, a in zip(cell_values, colaligns)
     ]
     return "".join(values_with_attrs) + "||"
@@ -690,7 +700,7 @@ def escape_empty(val):
         linebelowheader=None,
         linebetweenrows=None,
         linebelow=None,
-        headerrow=DataRow("|_. ", "|_.", "|"),
+        headerrow=DataRow("|_. ", "|_.", "|", {r"|": r"&#124;"}),
         datarow=_textile_row_with_attrs,
         padding=1,
         with_header_hide=None,
diff --git a/test/test_output.py b/test/test_output.py
index ea3da87..58659f2 100644
--- a/test/test_output.py
+++ b/test/test_output.py
@@ -2584,6 +2584,34 @@ def test_moinmoin_headerless():
     assert_equal(expected, result)
 
 
+def test_moinmoin_escapes_pipes():
+    "Output: moinmoin with literal pipes in cell and header content"
+    # https://github.com/astanin/python-tabulate/issues/501
+    expected = "\n".join(
+        [
+            '||<style="text-align: left;"> \'\'\' h &#124; 1   \'\'\' '
+            '||<style="text-align: left;"> \'\'\' h2     \'\'\' ||',
+            '||<style="text-align: left;">  x &#124; y    '
+            '||<style="text-align: left;">  a &#124;&#124; b  ||',
+        ]
+    )
+    result = tabulate([["x | y", "a || b"]], headers=["h | 1", "h2"], tablefmt="moinmoin")
+    assert_equal(expected, result)
+
+
+def test_textile_escapes_pipes():
+    "Output: textile with literal pipes in cell and header content"
+    # https://github.com/astanin/python-tabulate/issues/501
+    expected = "\n".join(
+        [
+            "|_.  h &#124; 1   |_. h2     |",
+            "|<. x &#124; y    |<. a &#124;&#124; b |",
+        ]
+    )
+    result = tabulate([["x | y", "a || b"]], headers=["h | 1", "h2"], tablefmt="textile")
+    assert_equal(expected, result)
+
+
 _test_table_html_headers = ["<strings>", "<&numbers&>"]
 _test_table_html = [["spam >", 41.9999], ["eggs &", 451.0]]
 _test_table_unsafehtml_headers = ["strings", "numbers"]