Phytochemicals possibly involved in biological functions are the basis of herbalism, and may be grouped as: For example, some secondary metabolites are toxins used to deter predation, and others are pheromones used to attract insects for pollination.
Secondary metabolites and pigments may have therapeutic actions in humans, and can be refined to produce drugs; examples are quinine from the cinchona, morphine and codeine from the poppy, and digoxin from the foxglove.
For example, the marsh mallow has the classification Althaea officinalis, as it was traditionally used as an emollient to soothe ulcers.
Examples of such derivatives include aspirin, which is chemically related to the salicylic acid found in white willow.
The opium poppy is a major industrial source of opiates, including morphine.