Even herbal repellents are harmful. Instead we use naturally at home. Sambrani dhoop cups is the best for mosquito's or as of now everywhere mosquito bat's are the best. I had checked out in net the natural way of repellent , the answer what I got, I tried but was not so effective as sambrani dhoop which my mother told me. It was just mix champor and neem oil and fill it in mosquito repellent bottle and use it by machine. But it was not so effective to me.