Phytohormones is a word derived from the Greek, meaning plant hormone. Plants, like human beings, have hormones, which can be described as 'chemical messengers'. These substances, manufactured and secreted in the body or plant, travel in the blood of the animal, or the plant's sap, and can influence functions in another part of the organism. They are involved in growth, reproduction and many other functions.

Some plant hormones are similar to human hormones in structure and function, and plants containing them can be used to help the hormone function in our own bodies. Notable among these are fennel, hops and willow-catkins, which all contain forms of the female hormone oestrogen, and sarsparilla which contains the male hormone testosterone.

Some of the essential oils which have an aphrodisiac effect may contain plant hormones too, but there is still a great deal to be learnt about these substances and their uses. When we know more about them, the actions of some essential oils will probably be better understood. It could well be that the oils which balance the menstrual cycle, increase the flow of breast milk, or strengthen contractions during childbirth, do so because of the presence of plant hormones, but this we will not know until a lot more research has been carried out.