Power of Herbs ( Dravyagunashastra )

Ayurveda uses herbs, foods and minerals according to their energetic qualities. a simple introduction to the theory of the pharmacology of Ayurveda is given below.

TASTE (RASA)
Tastes have certain functions and effects:

• Temperature: Each specific taste effects the thermo-regulatory qualities within the body; hot (ushna) and cold (shita). They heat it up or cool it down. For example, Cinnamon is pungent and hot which raises temperature whilst Grapes are sweet and cooling which can help to cool a fever.
• Quality: The taste also defines whether a herb is light (laghu) or heavy (guru) to digest and wet (snighda) or dry (ruksha) on the mucus membranes. An example is Black Pepper that is pungent and also hot, light and dry; it is easy to digest and dries the mucus membranes.
• Tropism: The taste also implies an affinity for certain tissues and organs. A herb will influence the function of an organ, tissue or channel by tonifying or reducing, stimulating or pacifying, drying or moistening. For example hot and dry herbs clear wet mucus from the lungs, whilst cool and bitter herbs drain heat from the blood and liver.
• Doshic: The taste of each medicinal also influences the quantity and quality of each dosha. For example, sweet builds kapha, reduces vata and pitta and increases all the tissues
• Direction: The taste has an effect on the movement of vata dosha by influencing the direction the five vayu move in: For example, the pungent taste ascends and spreads vyana vayu outward causing sweating whilst bitter descends causing apana vayu to move downwards with a laxative effect.

THE THERMAL ACTION OF HERBS AND FOODS (VIRYA)

Hot (ushna): Heat warms, dries, invigorates and stimulates the tissues. Just as the sun on a hot day causes the blood to come to the surface of the body, so energetically hot herbs cause our metabolism to expand upwards and outwards causing the pores of the skin to open. Heat increases the metabolism, encourages circulation, causes sweating, light headedness and thirst. Hot substances are usually used to treat cold, contracted and hypo or sluggish conditions. Beneficial to kapha and vata, it dries damp, phlegm and warms cold. As ‘like increases like’ pungent herbs encourage agni and digestion to function at optimum level. Herbs that are heating usually contain volatile oils or mustard glycosides that stimulate gastric secretions as well as assimilation of nutrients. Ushna substances have a particular affinity for the heart, head, liver and lungs and are commonly used when they are imbalanced but may damage them if used unjudiciously. Pungent, sour and salty herbs tend to be heating.

Cold (shita): Cold natured herbs cool, moisten and sedate the tissues and metabolism. Rather like the cold of a winter’s day causes you to shiver energetically cold herbs contract the muscles and narrow the channels of circulation. Cold substances are usually used to treat ‘hot’, inflamed and hyper conditions. Cold benefits pitta whilst aggravating kapha and vata; cold natured herbs soothe painful and inflammatory heat conditions. Digestion is easily damaged by cold natured herbs and should be used cautiously when there is diarrhoea and sluggish digestion from cold. Cold herbs have an affinity for the stomach, the kidneys and the bladder and can weaken them if used excessively. Bitter, astringent and sweet herbs tend to be cooling.

POST DIGESTIVE EFFECT (VIPAKA)

This is a unique energetic category peculiar to Ayurveda. Vipaka refers to the post-digestive effect of tastes; it is the effect a certain flavour has on the tissues having been digested or after cooking. It is the long-term effect of a food or herb. Vipaka results from the mixing of the digestive fire with the particular flavour:

Sweet and Salty flavours: Digest into sweet: sweet is nourishing and moistening to the tissues and also has a mildly laxative effect. The cooling and anti-inflammatory nature of sweet make it beneficial to pitta and its wet and building properties will increase kapha.
Sour: Digests into sour: this will encourage digestion, benefit the liver, increase heat and moisture in the body whilst also calming the nervous system. Its long-tem effect is to aggravate pitta and calm vata.
Pungent, Bitter, Astringent: Digest into pungent: its nature is to increase dryness, constipation and gas. This can help kapha and aggravate vata.

To give an example of how the vipaka varies according to the specific energetics of each herb we will look at the Peppers. Both Black Pepper (Piper nigrum) and Long Pepper (Piper longum) are pungent and heating. Whilst Black Pepper is pungent after digestion and therefore constipating, drying and damaging to the production of reproductive fluids, Long Pepper is sweet post digestively and therefore helps elimination, is moistening and is a beneficial rejuvenative tonic to kapha and as an aphrodisiac to the reproductive system. Onions and Ginger are other examples of herbs that are hot and irritating in the raw state but become less hot and sweeter and nourishing after cooking; both also have respected anti-inflammatory effects and promote the reproductive system.

THE QUALITIES OF THE HERBS (GUNA)

The specific ‘quality’ of a herb indicates its potential therapeutic activity.
There are twenty qualities listed in Sushruta but these five listed below are the main ones used in Ayurvedic herbal energetics:

Light (laghu)
Plants, foods and minerals that are light have a quality that moves upwards, are easily digested and also remove sluggishness and kapha. Aromatic and warming herbs often have a light quality. The bitter and astringent flavoured herbs are usually light in nature. Leaves, seeds and fruits are mainly light. The aromatic Cardamom (Elettaria cardamomum) seeds are light.

Heavy (guru)
Substances that are heavy sink downwards, are difficult to digest, increase kapha and nourish the whole system. They benefit vata by opposing its light, dry qualities. Heavy natured herbs are often sweet, salty or sour. Roots, resins, nuts and barks are often heavy. Ashwagandha (Withania somnifera) is heavy.

Unctuous (snigdha)
These medicinals are soft, demulcent and oily. They are strengthening, increase virility, fertility and kapha. They are usually sweet, heavy and contain a high content of volatile oils, mucilage or essential fatty acids. Sesame (Sesamum indicum) seeds and oil are unctuous.

Dry (ruksha)
Any plant with a dry quality is naturally astringent, absorbs moisture and therefore reduces kapha and increases vata. They are usually high in tannins and may also be heating as well (as heat dries fluids). Most plants have tannins in but certain barks and fruits are especially astringent. Haritaki (Terminalia chebula) is dry.
Penetrating or Sharp (tikshna)
Herbs with a penetrating or sharp quality are usually pungent, acrid and aromatic. They spread deeply into the tissues, open the channels and by their intense nature increase pitta and calm kapha and vata. Vacha (Acorus calamus) has penetrating properties.

THE UNIQUE ACTION OF A PLANT (PRABHAVA)

Ayurveda includes the descriptive category of prabhava or specific action. This term implies the individual action of a substance regardless of its taste, energy or post-digestive effect. It includes these concepts but is not dependent upon them. It is the specific action of a plant above and beyond its energetic classification.

For example, Tulsi (Ocimum sanctum) is classified as heating but it therapeutically helps to clear heat and reduce fever through diaphoresis. This means that whatever the causes of the fever Tulsi is indicated and this is its prabhava.

Sesame seeds (Sesamum indica) and Madanphala (Randia dumentorium) are both sweet, astringent and bitter in flavour but Sesame is a tonic whilst Madanphala is an emetic and reduces any excess of the doshas. Whilst they have similar flavours their actions are different. Each has their own unique and individual prabhava.