diff --git a/pandas/_testing/asserters.py b/pandas/_testing/asserters.py
index d52dabe47279a..9faf1ca791998 100644
--- a/pandas/_testing/asserters.py
+++ b/pandas/_testing/asserters.py
@@ -1158,7 +1158,10 @@ def assert_frame_equal(
         Specify how to compare internal data. If False, compare by columns.
         If True, compare by blocks.
     check_exact : bool, default False
-        Whether to compare number exactly.
+        Whether to compare number exactly. If False, the comparison uses the
+        relative tolerance (``rtol``) and absolute tolerance (``atol``)
+        parameters to determine if two values are considered close,
+        according to the formula: ``|a - b| <= (atol + rtol * |b|)``.
 
         .. versionchanged:: 2.2.0