diff --git a/doc/Makefile b/doc/Makefile
index dfbe6c28..ca7495b3 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -10,6 +10,8 @@ BUILDDIR      = _build
 
 # Put it first so that "make" without argument is like "make help".
 help:
+	@if [ ! -d venv ]; then echo "WARNING: There is no venv directory, did you forget to 'virtualenv venv'. Check building-the-docs file."; fi
+	@if [ ! "z$$(which $(SPHINXBUILD))" = "z$$(pwd)/venv/bin/sphinx-build" ]; then echo "WARNING: Did you forgot to 'source venv/bin/activate'"; fi
 	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
 
 .PHONY: help Makefile
@@ -17,4 +19,4 @@ help:
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
 %: Makefile
-	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
\ No newline at end of file
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)