diff --git a/Grid/threads/Pragmas.h b/Grid/threads/Pragmas.h
index d05f8ee9..4d713258 100644
--- a/Grid/threads/Pragmas.h
+++ b/Grid/threads/Pragmas.h
@@ -43,6 +43,7 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
 #ifdef _OPENMP
 #define GRID_OMP
 #include <omp.h>
+#warning "Grid is using OpenMP for host loops"
 #endif
 
 #ifdef GRID_OMP