diff --git a/docarray/document/pydantic_model.py b/docarray/document/pydantic_model.py
index b332c578a7c..6661de63f2c 100644
--- a/docarray/document/pydantic_model.py
+++ b/docarray/document/pydantic_model.py
@@ -59,6 +59,9 @@ def _blob2base64(cls, v):
             else:
                 raise ValueError('must be bytes')
 
+    class Config:
+        smart_union = True
+
 
 PydanticDocument.update_forward_refs()
 
diff --git a/tests/unit/test_pydantic.py b/tests/unit/test_pydantic.py
index 074f162852f..174caafedad 100644
--- a/tests/unit/test_pydantic.py
+++ b/tests/unit/test_pydantic.py
@@ -123,7 +123,13 @@ def test_with_embedding_no_tensor():
 
 @pytest.mark.parametrize(
     'tag_value, tag_type',
-    [(3, float), (3.4, float), ('hello', str), (True, bool), (False, bool)],
+    [
+        (3.0, float),
+        ('hello', str),
+        ('1', str),
+        (True, bool),
+        (False, bool),
+    ],
 )
 @pytest.mark.parametrize('protocol', ['protobuf', 'jsonschema'])
 def test_tags_int_float_str_bool(tag_type, tag_value, protocol):