diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 64d4a2f..ec790fe 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -24,7 +24,6 @@ jobs:
       matrix:
         tox_env:
           - py36
-          - py37
           - py38
           - py39
           - py310
diff --git a/lxml_html_clean/clean.py b/lxml_html_clean/clean.py
index 37cf3e0..3eeda47 100644
--- a/lxml_html_clean/clean.py
+++ b/lxml_html_clean/clean.py
@@ -90,15 +90,19 @@ def _has_javascript_scheme(s):
 # - 0A - Line Feed
 # - 0B - Vertical tab
 # - 0D - Carriage Return
-_ascii_control_characters = re.compile(r"[\x00-\x08\x0C\x0E-\x1F\x7F]")
+_ascii_control_characters_str = re.compile("[\x00-\x08\x0C\x0E-\x1F\x7F]")
+_ascii_control_characters_bytes = re.compile(b"[\x00-\x08\x0C\x0E-\x1F\x7F]")
 
 
-def fromstring(string):
+def fromstring(data):
     """
     Enhanced fromstring function that removes ASCII control chars
     before passing the input to the original lxml.html.fromstring.
     """
-    return lxml_fromstring(_ascii_control_characters.sub("", string))
+    if isinstance(data, bytes):
+        return lxml_fromstring(_ascii_control_characters_bytes.sub(b"", data))
+    else:
+        return lxml_fromstring(_ascii_control_characters_str.sub("", data))
 
 
 # This regular expression is inspired by the one in urllib3.
diff --git a/tests/test_clean.py b/tests/test_clean.py
index b22548b..11cc102 100644
--- a/tests/test_clean.py
+++ b/tests/test_clean.py
@@ -355,6 +355,12 @@ def test_ascii_control_chars_removed(self):
         cleaner = Cleaner()
         self.assertEqual(expected, cleaner.clean_html(html))
 
+    def test_ascii_control_chars_removed_from_bytes(self):
+        html = b"""<a href="java\x1bscript:alert()">Link</a>"""
+        expected = b"""<a href="">Link</a>"""
+        cleaner = Cleaner()
+        self.assertEqual(expected, cleaner.clean_html(html))
+
     def test_memory_usage_many_elements_with_long_tails(self):
         comment = "<!-- foo bar baz -->\n"
         empty_line = "\t" * 10 + "\n"
diff --git a/tox.ini b/tox.ini
index ce95032..8706ef5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py36,py37,py38,py39,py310,py311,py312,py313,mypy
+envlist = py36,py38,py39,py310,py311,py312,py313,mypy
 skipsdist = True
 
 [testenv]