diff --git a/pandas/core/strings/accessor.py b/pandas/core/strings/accessor.py
index f8df05a7022d1..9f8c9fa2f0515 100644
--- a/pandas/core/strings/accessor.py
+++ b/pandas/core/strings/accessor.py
@@ -1231,7 +1231,7 @@ def replace(self, pat, repl, n=-1, case=None, flags=0, regex=None):
             Regex module flags, e.g. re.IGNORECASE. Cannot be set if `pat` is a compiled
             regex.
         regex : bool, default True
-            Determines if assumes the passed-in pattern is a regular expression:
+            Determines if the passed-in pattern is a regular expression:
 
             - If True, assumes the passed-in pattern is a regular expression.
             - If False, treats the pattern as a literal string
@@ -1287,7 +1287,7 @@ def replace(self, pat, repl, n=-1, case=None, flags=0, regex=None):
 
         To get the idea:
 
-        >>> pd.Series(['foo', 'fuz', np.nan]).str.replace('f', repr)
+        >>> pd.Series(['foo', 'fuz', np.nan]).str.replace('f', repr, regex=True)
         0    <re.Match object; span=(0, 1), match='f'>oo
         1    <re.Match object; span=(0, 1), match='f'>uz
         2                                            NaN
@@ -1296,7 +1296,8 @@ def replace(self, pat, repl, n=-1, case=None, flags=0, regex=None):
         Reverse every lowercase alphabetic word:
 
         >>> repl = lambda m: m.group(0)[::-1]
-        >>> pd.Series(['foo 123', 'bar baz', np.nan]).str.replace(r'[a-z]+', repl)
+        >>> ser = pd.Series(['foo 123', 'bar baz', np.nan])
+        >>> ser.str.replace(r'[a-z]+', repl, regex=True)
         0    oof 123
         1    rab zab
         2        NaN
@@ -1306,7 +1307,8 @@ def replace(self, pat, repl, n=-1, case=None, flags=0, regex=None):
 
         >>> pat = r"(?P<one>\w+) (?P<two>\w+) (?P<three>\w+)"
         >>> repl = lambda m: m.group('two').swapcase()
-        >>> pd.Series(['One Two Three', 'Foo Bar Baz']).str.replace(pat, repl)
+        >>> ser = pd.Series(['One Two Three', 'Foo Bar Baz'])
+        >>> ser.str.replace(pat, repl, regex=True)
         0    tWO
         1    bAR
         dtype: object
@@ -1315,7 +1317,7 @@ def replace(self, pat, repl, n=-1, case=None, flags=0, regex=None):
 
         >>> import re
         >>> regex_pat = re.compile(r'FUZ', flags=re.IGNORECASE)
-        >>> pd.Series(['foo', 'fuz', np.nan]).str.replace(regex_pat, 'bar')
+        >>> pd.Series(['foo', 'fuz', np.nan]).str.replace(regex_pat, 'bar', regex=True)
         0    foo
         1    bar
         2    NaN