diff --git a/fastapi/sse.py b/fastapi/sse.py
index 37468ff582..9899b0e214 100644
--- a/fastapi/sse.py
+++ b/fastapi/sse.py
@@ -212,7 +212,10 @@ def format_sse_event(
             lines.append(f": {line}")
 
     if event is not None:
-        event = event.replace("\r", "").replace("\n", "").replace("\0", "")
+        if "\n" in event or "\r" in event:
+            raise ValueError("SSE 'event' must not contain newline characters")
+        if "\0" in event:
+            raise ValueError("SSE 'event' must not contain null characters")
         lines.append(f"event: {event}")
 
     if data_str is not None:
@@ -220,7 +223,10 @@ def format_sse_event(
             lines.append(f"data: {line}")
 
     if id is not None:
-        id = id.replace("\r", "").replace("\n", "").replace("\0", "")
+        if "\n" in id or "\r" in id:
+            raise ValueError("SSE 'id' must not contain newline characters")
+        if "\0" in id:
+            raise ValueError("SSE 'id' must not contain null characters")
         lines.append(f"id: {id}")
 
     if retry is not None:
diff --git a/tests/test_sse.py b/tests/test_sse.py
index 467c6d8b77..40715e39ac 100644
--- a/tests/test_sse.py
+++ b/tests/test_sse.py
@@ -246,36 +246,46 @@ def test_server_sent_event_cr_id_rejected():
         ServerSentEvent(data="test", id="42\rpwned")
 
 
-def test_format_sse_event_strips_newline_in_event():
+def test_format_sse_event_raises_on_newline_in_event():
     from fastapi.sse import format_sse_event
 
-    result = format_sse_event(event="chat\npwned", data_str="hello")
-    assert b"\npwned" not in result
-    assert b"event: chatpwned\n" in result
+    with pytest.raises(ValueError, match="newline"):
+        format_sse_event(event="chat\npwned", data_str="hello")
+
+
+def test_format_sse_event_raises_on_cr_in_event():
+    from fastapi.sse import format_sse_event
+
+    with pytest.raises(ValueError, match="newline"):
+        format_sse_event(event="chat\rpwned", data_str="hello")
+
+
+def test_format_sse_event_raises_on_null_in_event():
+    from fastapi.sse import format_sse_event
+
+    with pytest.raises(ValueError, match="null"):
+        format_sse_event(event="chat\x00pwned", data_str="hello")
 
 
-def test_format_sse_event_strips_cr_in_event():
+def test_format_sse_event_raises_on_newline_in_id():
     from fastapi.sse import format_sse_event
 
-    result = format_sse_event(event="chat\rpwned", data_str="hello")
-    assert b"\rpwned" not in result
-    assert b"event: chatpwned\n" in result
+    with pytest.raises(ValueError, match="newline"):
+        format_sse_event(id="42\npwned", data_str="hello")
 
 
-def test_format_sse_event_strips_newline_in_id():
+def test_format_sse_event_raises_on_cr_in_id():
     from fastapi.sse import format_sse_event
 
-    result = format_sse_event(id="42\npwned", data_str="hello")
-    assert b"\npwned" not in result
-    assert b"id: 42pwned\n" in result
+    with pytest.raises(ValueError, match="newline"):
+        format_sse_event(id="42\rpwned", data_str="hello")
 
 
-def test_format_sse_event_strips_cr_in_id():
+def test_format_sse_event_raises_on_null_in_id():
     from fastapi.sse import format_sse_event
 
-    result = format_sse_event(id="42\rpwned", data_str="hello")
-    assert b"\rpwned" not in result
-    assert b"id: 42pwned\n" in result
+    with pytest.raises(ValueError, match="null"):
+        format_sse_event(id="42\x00pwned", data_str="hello")
 
 
 def test_server_sent_event_negative_retry_rejected():