diff --git a/doc/proxy_collection.rst b/doc/proxy_collection.rst
index 56dc0d0..3edc218 100644
--- a/doc/proxy_collection.rst
+++ b/doc/proxy_collection.rst
@@ -80,7 +80,7 @@ Invalid Sample Generation (negative data)
 
 The :py:class:`~fgutils.proxy_collection.diels_alder_proxy.DielsAlderProxy`
 provides the functionality to generate Diels-Alder counter examples, i.e.,
-reactions where base on the structure a Diels-Alder graph transformation rule
+reactions where based on the structure a Diels-Alder graph transformation rule
 would be applicable but the reaction can not happen because the diene is for
 example in a fixed s-trans conformation.