Change of qualities and effects
The general qualities and effects of substances are changed due to several factors like matra (dose) samyoga (administration with other substances), svabhava (nature) and processes involved in the preparation etc.
Even poison, when taken in small quantity equal to a sesame seed, acts like nectar.
Kodrava (Paspalum scrobiculatum Linn) on its own cures raktapitta (haemorrhagic diseases or haemo therma) but when it is used along with substances which are vidahi (substances causing inflammation or burning sensation), it causes raktapitta.
In the same way, sesame seeds, having a quality of causing dermatosis, cure it when it is applied along with bhallitaka (Semicarpus anacardium).
Jaggery a non-digestive stimulant becomes a digestive stimulant when combined with substances like abhaya (TermioaIia chebula).
Ghee, which stimulates the gastric fire is given to a thirsty person with excessive gastric fire along with madana (beeswax)
Milk which is well known as a Jivaniya (life-prolonging) causes death when traces of poison are left in the body
Sthavara (vegetable and mineral) and jangama poisons (animal poison) though both are poisons, act as antidotes to one another.
By Inherent nature
By nature, mani (precious stones) and charms though not consumed, subside fever. Unboiled buttermilk increases kapha in the throat but subsides in the alimentary canal. Ghee, even with more unctuousness in it, does not have the quality of subsiding facial paralysis, while butter does have that quality though less unctuous.
Dry ginger is prepared from ardraka /fresh ginger (Zingiber officinale Rosc) but the process involved in its preparation makes dry ginger lighter (easily digestible)
Rice is heavy but the laja (fried patty) though prepared from rice are light.
Kulmasa(grains soaked with water and then fried) prepared from mudga /mung (Phaseolus mungo) after steam-boiling is changed in quality from grahi and laghu to bhedana and guru
Wheat has a quality good to the eyes but when it is fried in oil it become harmful for the eyes.
Mulaka /Radish (Raphanus sativus) is injurious to health as it provokes all doshas, but when it is cooked or boiled it subsides them.
By its own Action
Rice is light (easily digestible) in its quality but the treatment of frying and pounding applied in preparing prithuka (poha/parboiled and flattened paddy) changes the quality of lightness to heaviness.
The normal (not heated) buttermilk and dry ginger are more grahi in their action than the buttermilk which is boiled and ardraka (fresh ginger) respectively.
By Combinative action
Jaggery water becomes more effective in its diuretic quality than jaggery or water given separately.
Similarly, jaggery and curd are aphrodisiac and the item called rasala, prepared from jaggery and curd, is more aphrodisiac
Grapes (Vitis vinifera) though having a quality of subsiding doshas, if kept in utensils made of iron. become sour and provoke all the three doshas
Application of the paste of candana (Santalum album) as an unguent is cool-producing in its effect but if the paste is made very fine and applied thickly and allowed to dry, it will give an effect of heat (burning sensation) due to the blocking of the heat from the skin.
A paste of agaru (Aquilaria agallocha Roxb) having an opposite quality of candana (i. e. producing coolness) gives an effect of cooling if the paste is rough, wet and applied in a thin layer.
Due to the difference in the constitution of the person, cow milk having the quality of shramsana, acts as grahi
Due to the change in the age and position, administration of emetics etc is prohibited to obese, old and children
Milk is sweet, sara and cold but curd a product of milk is opposite in its qualities.
Ghee, also a product of milk is same in its qualities to milk.
Milk and curd subside vata but unformed curd provokes vata
Meat of peacock is not very wholesome for general health but it is wholesome for ears, voice, and eyes. Though eyes and ears are predominantly formed with the elements fire and wind, substances which are cold and hot to touch are respectively wholesome.
As a normal procedure administration of emetics is prohibited in chardi (vomitting). heart ailments, and tumors. But it is advised in certain special cases, in chardi where the provocation of the doshas is very high to evacuate all the vitiated doshas and in cases of heart diseases and tumors where the vita dosha is obstructed by kapha, vomitting is advised.
Generally, basti is prohibited in the diseases of arshas (piles) and kushta (skin disorders) but in certain specific cases, i.e, when vata is provoked and when there is severe dryness in kustha, basti is permitted.
By Nature of Disease
Venesection is prescribed in diseases which are caused due to the vitiation of blood but in raktapitta (haemotherma) venesection is prohibited, though it is also caused by vitiated blood
The same food which is wholesome to the persons afflicted by eye disorders, becomes unwholesome during night
Dried saktu is unwholesome to all but wholesome only to a person of prameha disease
By daysleep, the food eaten on the previous day or night is digested but the food, which has been eaten on the same day is not digested
Scorpions are produced from the decomposed bodies of snakes but the same snakes die due to the sting of scorpion.