My wife and I recently trekked through Vietnam for over a month from the hills beyond Sapa to Jungles near Cambodia. Strange honeymoon but we loved it. We got a lot of Mosquito bites, even with DEET spray on. My wife cant take antibiotics so we purchased the Malaria Spray for our journey and then Andrew reminded us that Dengue fever was probably more prominent, so we bought the Dembarrah 200 as well. We relied purely on these sprays to cover us. That was 3 months ago. We have had no problems and considering our locale we feel the spray were an excellent insurance.