Human beings have always been intrigued with the hidden properties of plants. We generally see plants as being either useless or useful.

But there are also those plants which are dangerous. Herbal medicine studies the biological effects of vegetal essences on human biochemistry; those plants that we don't think of (mushrooms, seaweed, lichens, ferns, musk) are included.

Vegetal essences are chemical substances. Most of them have such a complex molecular structure, that no chemical laboratory has been capable of reproducing them. Considering that only small part of vegetal biochemical molecules have been analyzed, it is understandable that this field is still relatively unexplored.

Chemical substances can be grouped in these categories:

• Alkaloids. Very complex substances, active on our nervous system.
• Steroids. Molecules active as hormones
• Tannins. Bitter substances that have an astringent effect
• Saponins. Molecules very similar to soap ones, but more pure and sophisticated.
• Vitamins All vitamins, that our body does not produce can be found in plants (except for D vitamin, that can be synthesized with the help of the sunshine)
• Mucus Fibers that retain water with emollient effect