diff --git a/CHANGES/4218.misc b/CHANGES/4218.misc
new file mode 100644
index 00000000000..1cb60297f81
--- /dev/null
+++ b/CHANGES/4218.misc
@@ -0,0 +1 @@
+Add two more types to LooseCookies.
diff --git a/CHANGES/4250.misc b/CHANGES/4250.misc
new file mode 100644
index 00000000000..1c6cbe559d0
--- /dev/null
+++ b/CHANGES/4250.misc
@@ -0,0 +1 @@
+Add two more types to LooseCookies with tests for the allowed types.
diff --git a/CONTRIBUTORS.txt b/CONTRIBUTORS.txt
index b7e05b07a13..6af2ebd63ea 100644
--- a/CONTRIBUTORS.txt
+++ b/CONTRIBUTORS.txt
@@ -1,6 +1,7 @@
 - Contributors -
 ----------------
 A. Jesse Jiryu Davis
+Adam Bannister
 Adam Cooper
 Adam Mills
 Adrián Chaves
diff --git a/aiohttp/cookiejar.py b/aiohttp/cookiejar.py
index ac102bfc487..2d858de0e18 100644
--- a/aiohttp/cookiejar.py
+++ b/aiohttp/cookiejar.py
@@ -124,7 +124,7 @@ def update_cookies(self,
             return
 
         if isinstance(cookies, Mapping):
-            cookies = cookies.items()  # type: ignore
+            cookies = cookies.items()
 
         for name, cookie in cookies:
             if not isinstance(cookie, Morsel):
diff --git a/aiohttp/typedefs.py b/aiohttp/typedefs.py
index 3c42f6abe30..9154993cdbb 100644
--- a/aiohttp/typedefs.py
+++ b/aiohttp/typedefs.py
@@ -29,7 +29,7 @@
     _CIMultiDictProxy = CIMultiDictProxy[str]
     _MultiDict = MultiDict[str]
     _MultiDictProxy = MultiDictProxy[str]
-    from http.cookies import BaseCookie  # noqa
+    from http.cookies import BaseCookie, Morsel  # noqa
 else:
     _CIMultiDict = CIMultiDict
     _CIMultiDictProxy = CIMultiDictProxy
@@ -43,8 +43,20 @@
                      _CIMultiDictProxy]
 RawHeaders = Tuple[Tuple[bytes, bytes], ...]
 StrOrURL = Union[str, URL]
-LooseCookies = Union[Iterable[Tuple[str, 'BaseCookie[str]']],
-                     Mapping[str, 'BaseCookie[str]'], 'BaseCookie[str]']
+
+StrBaseCookieTuples = Iterable[Tuple[str, 'BaseCookie[str]']]
+StrMorselTuples = Iterable[Tuple[str, 'Morsel[str]']]
+StrToBaseCookieMapping = Mapping[str, 'BaseCookie[str]']
+StrToMorselMapping = Mapping[str, 'Morsel[Any]']
+LooseCookies = Union[
+    StrBaseCookieTuples,
+    StrMorselTuples,
+    Iterable[Tuple[str, str]],
+    StrToBaseCookieMapping,
+    StrToMorselMapping,
+    Mapping[str, str],
+    'BaseCookie[str]',
+]
 
 
 if sys.version_info >= (3, 6):
diff --git a/tests/test_cookiejar.py b/tests/test_cookiejar.py
index a024364b787..082dce676ce 100644
--- a/tests/test_cookiejar.py
+++ b/tests/test_cookiejar.py
@@ -3,7 +3,7 @@
 import itertools
 import pathlib
 import unittest
-from http.cookies import SimpleCookie
+from http.cookies import SimpleCookie, BaseCookie, Morsel
 from unittest import mock
 
 import pytest
@@ -662,3 +662,20 @@ async def test_dummy_cookie_jar() -> None:
         next(iter(dummy_jar))
     assert not dummy_jar.filter_cookies(URL("http://example.com/"))
     dummy_jar.clear()
+
+
+async def test_loose_cookies_types() -> None:
+    jar = CookieJar()
+
+    accepted_types = {
+        'StrBaseCookieTuples': [('str', BaseCookie())],
+        'StrMorselTuples': [('str', Morsel())],
+        'StrStrTuples': [('str', 'str'), ],
+        'StrToBaseCookieMapping': {'str': BaseCookie()},
+        'StrToMorselMapping': {'str': Morsel()},
+        'StrToStrMapping': {'str': 'str'},
+        'BaseCookie[str]': SimpleCookie(),
+    }
+
+    for name, loose_cookies_type in accepted_types.items():
+        jar.update_cookies(cookies=loose_cookies_type)