diff --git a/hyper/http20/util.py b/hyper/http20/util.py
index b116d095..ca5547d0 100644
--- a/hyper/http20/util.py
+++ b/hyper/http20/util.py
@@ -52,9 +52,9 @@ def h2_safe_headers(headers):
     """
     stripped = {
         i.lower().strip()
-        for k, v in headers if k == 'connection'
-        for i in v.split(',')
+        for k, v in headers if k == b'connection'
+        for i in v.split(b',')
     }
-    stripped.add('connection')
+    stripped.add(b'connection')
 
     return [header for header in headers if header[0] not in stripped]
diff --git a/test/test_hyper.py b/test/test_hyper.py
index 59d354c7..6a18d592 100644
--- a/test/test_hyper.py
+++ b/test/test_hyper.py
@@ -1176,27 +1176,27 @@ def test_nghttp2_installs_correctly(self):
         assert True
 
     def test_stripping_connection_header(self):
-        headers = [('one', 'two'), ('connection', 'close')]
-        stripped = [('one', 'two')]
+        headers = [(b'one', b'two'), (b'connection', b'close')]
+        stripped = [(b'one', b'two')]
 
         assert h2_safe_headers(headers) == stripped
 
     def test_stripping_related_headers(self):
         headers = [
-            ('one', 'two'), ('three', 'four'), ('five', 'six'),
-            ('connection', 'close, three, five')
+            (b'one', b'two'), (b'three', b'four'), (b'five', b'six'),
+            (b'connection', b'close, three, five')
         ]
-        stripped = [('one', 'two')]
+        stripped = [(b'one', b'two')]
 
         assert h2_safe_headers(headers) == stripped
 
     def test_stripping_multiple_connection_headers(self):
         headers = [
-            ('one', 'two'), ('three', 'four'), ('five', 'six'),
-            ('connection', 'close'),
-            ('connection', 'three, five')
+            (b'one', b'two'), (b'three', b'four'), (b'five', b'six'),
+            (b'connection', b'close'),
+            (b'connection', b'three, five')
         ]
-        stripped = [('one', 'two')]
+        stripped = [(b'one', b'two')]
 
         assert h2_safe_headers(headers) == stripped