Man has always used plants to try and cure himself, and signature theory is the link that may exist between the shape or appearance of a plant or fruit and its therapeutic power.
In the Middle Ages, signature theory was widely used, and is still going strong today.
People of the time believed that God had left his signature in plants and fruit to help man heal himself.
2 groups of signatures were defined:
– Intrinsic signatures, specific to the plant itself, such as walnuts, tomatoes, carrots…
In walnuts, the kernels resemble the hemispheres of the brain, and the signature theory deduces that they have a beneficial effect on brain function.
Beans are said to be kidney-shaped, and to have a beneficial effect on the kidneys.
The 2nd group of signatures:
– extrinsic signatures linked to the plant’s environment, such as the willow with its feet in the water that gave us aspirin.
When Edward Stone observed a white willow in the 18th century, he exclaimed: “This tree that grows with its feet in water is never sick! It must contain compounds against fever and chills”.
This signature theory was abandoned for lack of rigorous scientific argument, but in the case of willow, for example, aspirin is made from its French bark.In ancient Greece, decoctions of willow leaves were used.

In 400 BC. Hippocrates, the father of medicine, used it to treat fever and pain. Pedanius Dioscorides, born between 20 and 40 A.D., used the bark to make his secret decoctions.
The active principle of white willow would not be discovered until much later: in 1825, Italian pharmacist Francesco Fontana succeeded in isolating salicin.
In 1829, another French pharmacist, Pierre-Joseph Leroux, optimized the process by reducing a decoction of white willow bark to powder, then filtering and concentrating it to obtain white, water-soluble crystals, which he named salicyline, since the Latin word for willow is salix.
Although in the West, the power of food was recognized, the most widespread form of divination in the 19th century did not use food as a medium for divination, and the practice of using coffee grounds, eggs and tea leaves remained in the minority, unlike Tarot readings, Oracles and palm readings, which were in the majority.
Animal scarification was no longer used.
Food is a basis for divination like any other.
It’s the clairvoyant’s connection to his or her Guides that counts. You can even create your own medium with a food or object with which you feel able to interact and create your own Cards and Oracles.
In recent years, these culinary divination methods have gained in popularity.

Caffeomancy uses coffee grounds.