Decoctions v's Infusions in Ayurvedic and Western Herbal Medicine
Posted on 03 March 2017 by Leonie Satori
Herbal decoctions and infusions are easy to make at home and although an often overlooked way to administer herbs, actually have great therapeutic value in modern herbal medicine today. This article looks at a comparison between the history and usage of decoctions and infusions and their value in Western Herbal Medicine and in Eastern Ayurvedic Medicine.
Introduction to an Ayurvedic perspective of decoctions and infusions
Decoctions (kwatha), hot infusions (phanta kalpana) and cold infusions (hima kalpana) are considered in Ayurvedic medicine as part of the Panchavidha Kashaya Kalpanas or the five primary medicinal preparations and have been an integral part of Ayurvedic therapies for centuries. These primary medicinal preparations can be used alone or can also form the basis of secondary preparations that are more complex in their structure. The five primary medicinal preparations are graded according to their strength, with decoctions considered to be more potent than both types of infusion, and cold infusions more potent than hot infusions.
What is a decoction?
A decoction is a medicine that is prepared by boiling or simmering an herb and water mixture. With Ayurvedic tradition, one part of coarsely powdered herb is simmered with 16 parts of water in an earthen pot over a mild fire until the liquid is reduced to half of the original quantity; the proportions of herb to water can vary according to the coarseness of the herbs or the quantity of the herbs used. In practice the Ayurvedic philosophy says that the vessel should not be covered by a lid during the preparation as this will produce a decoction that is not considered to be easily digestible. This is due to the accumulation of drops on the lower surface of the lid mixing again with the preparation, disturbing its potency.
The Western Herbal method for preparation of a decoction involves the use of 30 grams of herb in 4 cups of water which is then allowed to simmer for up to 10 minutes or until the mixture is reduced to 3 cups. After such time, lighter herbs such as leaves or flower petals can be added, and then the mixture can be steeped (with the lid on) for ten minutes or so.
The decoction generally has a lifespan of 24 hours, after such time they tend to lose their potency and the risk of fungal contamination is increased with prolonged storage, however you can refrigerate the decoction to prolong the life for several days. The dosage for decoctions can be smaller and of greater frequency – owing to their higher and sometimes quite concentrated potency. They can be very effective for acute conditions, with doses administered from one tablespoon up to 150mL given at regular intervals.
What are the different types of decoctions?
In Ayurveda there are several different types of decoctions that are used in therapeutics, and many of these are long forgotten by the modern Western Herbalist as viable medicinal preparations. Ayurveda recognises amongst others, meat soups or broths (called mamsarasa) for building strength and providing nourishment and simple boiled and reduced water (called usnodaka) to aid in elimination of toxins and as a treatment for respiratory disorders.
Another popular type of decoction is a kshira paka or a milk decoction; it is prepared by combining water and milk to provide a versatile solvent for the extraction of additional active constituents. Kshira paka is used to increase palatability of astringent or sharp herbs such as Terminalia arjuna or garlic and improves the extraction of protein and lipid soluble portions of the herbs.
What is an infusion?
Like a decoction, infusions are a simple combination of herb and water. An infusion effectively requires soaking of herbs in either cold or freshly boiled water for a period of time, until the water portion of the mixture has attained some of the medicinal qualities of the herbs. Infusions are predominantly used for the leafy or flower parts of plants as opposed to the barks or roots used to make decoctions, the exception for this is where they can be finely ground.
In modern Western Herbal medicine, infusions that are made from fresh herbs should first be bruised, 30grams of dried or fresh herb is covered with 3 cups of boiling water and left to steep for anywhere between 10 and 30 minutes. Dosages are usually given in cup measures. Where the extraction of the mucilage of the herb is of priority, the herb is initially soaked in its equivalent weight in cold water for 15 minutes then the rest of the hot water is added. It is also believed that it is best to cover the infusion whilst steeping to reduce the loss of volatile constituents and to maintain a high temperature for maximum extraction of constituents. As with decoctions, infusions are best consumed immediately (or at least within 24 hours). Due to the ease of fungal or bacterial contamination they are best not stored for longer than this.
What are the different types of infusions?
As mentioned earlier, Ayurveda considers two classifications of infusions, hot and cold: Cold infusions are used when the herbs contain volatile principles that may be destroyed with heating; the cold infusion preserves these active principles. Generally one part of the herb is soaked in 3-8 parts of water overnight and the liquid portion is collected for use as medicine. The diversity of cold infusions means that not only herbs can be used for soaking in cold water, but also grains and fruits can be used and the ‘soak-water’ can be utilised for it’s therapeutic effect.
Hot infusions are considered in Ayurveda to be the least potent of the five primary medicinal preparations; they can be compared to the modern Western Herbal infusion. Due to their lower potency, hot infusions are considered to be the best preparation for children.
What are decoctions and infusions used for?
Decoctions and infusions can be used as medicines in themselves - either for ingestion or as cleansing or nourishing enemas, as eye washes, douches, herbal hair rinses, face washes or to help cleanse and heal an abrasion or wound. Other effective ways for administering the water soluble constituents from decoctions and infusions is in the preparation of secondary medicines – such as pills, creams, jams, medicated oils and ghee or in the preparation of a poultice or compress.
In Ayurvedic tradition, decoctions and hot infusions are used in the vata seasons (winter) and for vata constitutions and disorders, being that they are warm, nourishing and easy to digest. Whereas cold infusions tend to be used in the summer months and in the treatment of pitta constitution people and disorders, because of their more cooling quality. In Western Herbal medicine, decoctions are often used short-term due to their strong concentration; they can be used for headaches, migraines, colds, infections, pain, and nausea. Infusions tend to be a little weaker than decoctions, and are generally used for problems that are more mid-long term.
Both decoctions and infusions can be used in cases where the person is unable to consume herbs in any other way, even when the preparation cannot be consumed orally, an infusion or decoction of herbs can be used as an enema. Infusions and decoctions are traditionally most effective for the treatment of urinary tract disorders, kidney disorders and are useful for the administration of alterative herbs. Diaphoretic herbs are also best administered as decoctions or hot infusions to maximise their effectiveness. Other uses are for the treatment of respiratory complaints, colds, coughs, anxiety, nervousness or sleeplessness. Digestive complaints such as bloating, gas or wind can also benefit from decoctions or infusions of specific herbs, also indigestion, constipation and really a whole list of ailments can be treated with aqueous preparations, provided the constituents required for the medicinal action are water soluble.
Pharmacokinetics and bioavailability
Although several phytochemicals are water soluble, it is often considered by modern Herbalists that infusions and decoctions are inferior preparations for extraction and delivery of herbal actives except where the actives are largely water soluble. Therefore I will mainly focus on predominant constituents such as mucilage, tannins, volatile oils and glycosides such as saponins in the explanations of pharmacokinetics of constituents of aqueous extracts.
Herbs having high mucilage content tend to have a direct action in the digestive system and also an embryonic reflex action in other systems of the body like the respiratory system and urinary system. These constituents are essentially not digested, but their hydrophilic quality enables a cooling and soothing topical action. Therefore an herb such as Althea officinalis (marshmallow) is not only useful as an antitussive, but can be effective in treating digestive complaints or urinary disorders requiring demulcent action, making such herbs ideal for aqueous applications such as decoctions or infusions.
Tannins, again have their main application locally as their primary action is astringency due to their precipitation of proteins, and, like mucilage are not generally absorbed for secondary actions. Herbs such as Agrimonia eupatoria (Agrimony), known for it’s astringency and high tannin content is therefore effective in aqueous extracts for the treatment of sore throats (as a gargle) – to reduce inflammation, to treat digestive disorders such as diarrhoea or mucous colitis or for urinary incontinence.
Aqueous extracts are particularly beneficial where topical action is required. Herbs with high amounts of mucilage can be used for their emollient quality in the treatment of lesions, wounds and abrasions. Other topical applications are where open wounds need to be sealed and closed – this is where high tannin herbal infusions or decoctions are useful for binding proteins and sealing the skin.
When using herbs with high volatile oil content in aqueous preparations (typically infusions), the hot water acts like a distillation medium and the oil will tend to collect on the surface of the water. The constituents of essential oils exert their first actions on the olfactory system, connecting to the limbic system which influences sensory functions such as hunger, sex and emotions. Due to their small molecular size and strong lipophilic nature, volatile oils are readily absorbed into the body and across the blood-brain-barrier. Their therapeutic action often dependant on their chemical functional groupings, allowing several differing actions being attributed to this broad class of phytochemicals. The possibility of multiple actions is displayed in herbs such as Matricaria recutita (Chamomile) with relaxing nervous system affects and carminative actions in the digestive system which are naturally enhanced through an infused extraction.
Excretion of volatile oils occurs through the kidneys, so an herb such as Agathosma betulina (Buchu) also exerts its urinary antiseptic qualities through its volatile oils best when administered in an aqueous extract. One of the traditional ways of increasing the solubility of particular compounds that are not as water soluble in a decoction or infusion is by the addition of saponin containing herbs – resulting in overall better bioavailability of the herbal constituents. Saponins are considered to be poorly absorbed in the gut, however, the conversion of their glycoside into aglycone in the large intestine renders them more lipid soluble and they will be more bioavailable as the aglycone.
Many herbs whose main active constituents are saponins are antitussives and expectorants, relaxing via reflex action and, when used in combination with other herbs are believed to increase the absorption of active constituents. Glycyrrhiza glabra (Liquorice) is an example of such an herb that is used both solely for its therapeutic action and as an adjuvant in aqueous herbal preparations to enhance the overall effect of the herbs.
Water is the common carrier of constituents in both decoctions and infusions, and although both preparations are very primitive, they have a wide range of solvent action – alkaloids, glycosides, tannins, proteins, sugars, anthraquinones, gums, mucilage, enzymes, minerals and colouring matter. With this list of possible active constituents in a water extraction like decoctions and infusions, it is a wonder why so many Herbalists prefer to use either solid preparations (tablets or capsules) or alcoholic extractions. Essentially, it is the primitive nature of these preparations that decreases their fashion in modern society. Although they are simple to prepare, pretty much non-toxic and on the part, easily available and inexpensive, they are however, time consuming and impractical to the modern consumer. As mentioned earlier, these preparations are required to be consumed almost immediately otherwise risking bacterial or fungal overgrowth, thus reducing their shelf life. Often the taste of the herbal preparation also can be off-putting, especially if a person is required to consume several cups of foul tasting decoction or infusion on a daily basis. However, it is the summation of the repeated gentle effects of herbal infusions and decoctions that is the reason why they are often surprisingly effective.
In a modern practice today, specificity of effectiveness is the key to appropriately prescribing herbal decoctions or infusions. Reliance on simple preparations such as these could result in decreased therapeutic benefit, however using them as a complement or an adjunctive therapy would provide more of a thorough treatment therapy.
An interesting example of this is in the way that Ayurveda uses anupanas or vehicles for administration of medicines. Anupanas are considered a very important factor that helps in the absorption and assimilation as well as the efficacy of the medicines. Generally the anupana will depend on the condition of the patient and the vitiated doshas, an example of this is the use of usnodaka, the simple water decoction mentioned earlier. Usnodaka is used as an adjunctive therapy when using medicated ghee preparations, the combination of therapies enhance the activities of the primary focus of the therapy, which is the medicated ghee preparation, thus ensuring a thorough and whole recovery from illness. On the whole, both decoctions and infusions can still play a major role in modern Herbal Medicine and Phytotherapy, their uses only being restricted by the imagination of the practitioner and consumer alike.
About the Author
Leonie is a Naturopath & Medical Herbalist with a passion for good food, healthy living and of course, herbal medicine. When she is not consulting in her Naturopathic clinic in Lismore or blogging about nutrition, Ayurvedic Medicine or natural health, she is studying yoga, growing her own herbs and vegetables or quietly walking in the natural bush land in Northern Rivers NSW.
Contact our health centre in Lismore to book an appointment with Leonie in our naturopathic clinic.
The content of this website and any provided materials, research, or communications are for informational purposes only. The content is not intended to be a substitute for professional health advice, diagnosis, or treatment. Always seek the advice of your qualified health practitioner with any questions you may have regarding your health condition.