diff --git a/slow/slow.py b/slow/slow.py
index b7c8f42..abd4725 100644
--- a/slow/slow.py
+++ b/slow/slow.py
@@ -100,7 +100,7 @@ class App:
         method: str,
         func: Callable[[Request, ...], Awaitable[Response]],
     ):
-        if method not in ["GET", "POST", "PUT", "DELETE"]:
+        if method not in ["GET", "POST", "PUT", "DELETE", "PATCH", "HEAD"]:
             raise RuntimeError(f'Invalid method "{method}".')
         pat = self._pattern_to_regex(path)
         if pat not in self.routes: