Acharya Keshav Dev, a yoga master who has authored several books on the more esoteric, less known aspects of yoga, contributes one full chapter to the subject of fragrances in his book A Mystery. He writes of Dhoomra chikitsa (therapy of fumes) and gandha vidya (science of fragrances) as separate branches of yoga. He lists a few flowers in this chapter. Rose, he observes, was used as an aphrodisiac. Lotus was used to heighten meditation. Balsam flowers cured insomnia. The common hyacinth regarded as pest these it was used to control cardiac problems and anxiety. On the aesthetic front, it helped in hair growth, as did hibiscus flower (used also as a natural hair dye and conditioner to keep hair silky and manageable).