diff --git a/dune/fufem/improvegrid.hh b/dune/fufem/improvegrid.hh
index 46aa8692779ffdd4df738f799a875f187d8be0f5..c040958c357d66cc96b4d0d5ab4e9e3c0637ce78 100644
--- a/dune/fufem/improvegrid.hh
+++ b/dune/fufem/improvegrid.hh
@@ -62,6 +62,11 @@ double aspectRatio(const EntityType& entity)
 
 }
 
+/** \brief Improve maximal aspect ratio of the grid by moving vertices.
+ *
+ *  \param grid The grid
+ *  \param threshold The threshold on the aspect ratio that determines which elements should be refined.
+ */
 template <class GridType>
 void improveGrid(GridType& grid, double threshold)
 {