diff --git a/dataframe-core/src-internal/DataFrame/Internal/DataFrame.hs b/dataframe-core/src-internal/DataFrame/Internal/DataFrame.hs
index ee0961f4..23319357 100644
--- a/dataframe-core/src-internal/DataFrame/Internal/DataFrame.hs
+++ b/dataframe-core/src-internal/DataFrame/Internal/DataFrame.hs
@@ -335,10 +335,20 @@ toSeparated sep df
         let (rows, _) = dataframeDimensions df
             headers = map fst (sortBy (compare `on` snd) (M.toList (columnIndices df)))
             sepText = T.singleton sep
-            headerLine = T.intercalate sepText headers
-            dataLines = map (T.intercalate sepText . getRowAsText df) [0 .. rows - 1]
+            escape = escapeField sep
+            headerLine = T.intercalate sepText (map escape headers)
+            dataLines =
+                map (T.intercalate sepText . map escape . getRowAsText df) [0 .. rows - 1]
          in T.unlines (headerLine : dataLines)
 
+-- | RFC 4180: quote fields with sep, quote or newline; double inner quotes.
+escapeField :: Char -> T.Text -> T.Text
+escapeField sep t
+    | T.any needsQuoting t = "\"" <> T.replace "\"" "\"\"" t <> "\""
+    | otherwise = t
+  where
+    needsQuoting c = c == sep || c == '"' || c == '\n' || c == '\r'
+
 getRowAsText :: DataFrame -> Int -> [T.Text]
 getRowAsText df i = map (`showElement` i) (V.toList (columns df))
 
diff --git a/tests/IO/CSV.hs b/tests/IO/CSV.hs
index e015ab2e..a020ae2e 100644
--- a/tests/IO/CSV.hs
+++ b/tests/IO/CSV.hs
@@ -86,6 +86,19 @@ fromCsvSingleColumn = TestLabel "fromCsv_single_column" $ TestCase $ do
             assertEqual "rows" 3 (D.nRows df)
             assertEqual "columns" 1 (D.nColumns df)
 
+-- | Round trip: fields holding separators, quotes and newlines survive.
+fromCsvRoundTripQuoted :: Test
+fromCsvRoundTripQuoted = TestLabel "fromCsv_roundTrip_quoted" $ TestCase $ do
+    let df =
+            D.fromNamedColumns
+                [ ("a,b", DI.fromList @T.Text ["x,y", "he said \"hi\"", "line1\nline2"])
+                , ("c", DI.fromList @Int [1, 2, 3])
+                ]
+    result <- fromCsv (T.unpack (toCsv df))
+    case result of
+        Left err -> assertFailure $ "Unexpected Left: " ++ err
+        Right df' -> assertEqual "round trip data" df df'
+
 tests :: [Test]
 tests =
     [ fromCsvHappyPath
@@ -94,4 +107,5 @@ tests =
     , fromCsvRoundTrip
     , fromCsvBytesRoundTrip
     , fromCsvSingleColumn
+    , fromCsvRoundTripQuoted
     ]