Visha means poison. Visha Chikitsa or Agada Tantra include the treatment of diseases caused by poisons and toxins, such as spoilt food, animal, reptile and insect bites, poisonous minerals, metals and unsuitable food combinations . It is equivalent to toxicology in modern medicine.
Visha Chikitsa describes the action of harmful elements on body functions and how it can destroy the body tissues. Specific antidotes for poisons were prescribed for nullifying its effects. Ancient texts such as Charaka Samhitha, Susrutha Samhitha and Ashtanga Sangraha offer exhaustive information on this branch of Ayurveda.
Several drugs of plant origin have been used to treat various disorders, e.g. reserpine, atropine, etc. by modern system of medicine. However, many of them were withdrawn or are obsolete due to their toxicity. But ancient science of medicine is using all such substances since ages in their crude form or after proper process of refinement and detoxification called shodhana. . In addition, science of Ayurveda classify many herbal drugs as visha (poison) or upa-visha (moderately poisonous) and also uses them after shodhana . According to Ayurveda, shodhana is not only the process of detoxification, but also a process of Samaskara (potentiating the therapeutic efficacy) of such drugs. It also reduces the side effects. In modern literature, there is not much information regarding the scientific validity and rationale in adopting specific shodhana process for herbal drugs. There is some information regarding the ancient Chinese method of detoxification of some of the herbs like nux-vomica. According to literature, Chinese method of detoxification reduced the toxicity and enhanced the potency of seeds of nux- vomica. Further they attributed this to the qualitative and quantitative changes in the phytochemical profile of the seeds due to detoxification process.
Etymologically, ‘Visha’ is that which causes ‘Vishannatva’ (distress) and / or vishada (sadness) in the body. Thus ‘Visha’ has been defined as a substance which is destructive to life and possess properties like Vyavayi, Vikasi, Ushna, Tikshna, Ruksha, Sukshma, Ashukar, Anirdeshya rasa / Apaki etc.. And the drugs which possess these properties are called ‘Vishas’ and those which are less in virulence than ‘Vishas’ are called ‘Upavishas’ (sub-poisons).
Vedic literature explained the mode of drug action due to inherent power (Veerya).
It was long ago when Ayurvedic fundamentals and its eight clinical features were documented in the Ayurvedic literatures.
Initially Dravyaguna shastra was not mentioned as a separate branch of Ayurveda. But all the treatises contain elaborate descriptions about the herbs, their properties and indications. Charaka identified the necessity of complete knowledge of herbs and their utility in therapeutics. Charaka opined that a deadly poison can become a very good medicine if it is administered properly.
Classification of Poison
The classification of poison is based on certain basic criteria like origin, base, properties, potency etc. Some of the Ayurvedic classics and texts in medieval period have classified all the poisons into two categories as Mahavisha and Upavisha basing on their toxicity and potency.
Upavisha are the group of drugs, which are less toxic in nature and not so lethal but produce certain toxic symptoms on consumption or administration. The symptoms produced in the body due to Upavisha are less toxic, less severe, usually not life threatening and their toxicity can be controlled by therapeutic measures.
Broadly ‘Vishas’ are classified into three types viz. Sthavara, Jangam and Kritrima. ‘Sthavara Vishas’ are those which belong to minerals or to group of poisonous herbs, while ‘Jangama Vishas’ are obtained from the animal kingdom. The ‘Kritrima Vishas’ are formed as a result of undesired compounding of drugs. Among the poisonous herbs- tuberous and / or root poisons are more toxic.
In literature, ‘Rasarnava’ appears to be the first text to mention about ‘Visha’ ‘Upavisha’ classification. After ‘Rasarnava’, ‘Rasa Ratnakara’, ‘Rasendra Chudamani’ and ‘Rasa Ratna Samucchaya’ have mentioned about five ‘Vishas’ while other texts like ‘Rasendra Chintamani’, ‘Sarngadhara Samhita’, Bhava Prakasha and Ayurveda Prakasha have enumerated nine dravyas as ‘Vishas’. The Author of ‘Rasatarangini’ (20th A D) described only ‘Vatsanabha’ in ‘Visha’ group considering its medicinal importance, common availability and frequent use in therapeutics. The other drugs of poisonous nature have been included in ‘Upavisha’ group by this text.
Poisons in Ayurvedic literature While reviewing the Ayurvedic literature for visha, it is found that there is a difference of opinion amongst the authors regarding the inclusion of drugs in ‘Upavisha’ group. ‘Rasarnava ’ mentioned five drugs in ‘upavisha group, while ‘Rasaratna Samucchaya’ and ‘Rasendra Chintamani ’ enumerated seven drugs; in later texts like ‘Ayurveda Prakasha’ and ‘Yogaratnakara’ it is increased to nine while in ‘Rasa Tarangini it has gone up to eleven. Thus, historically, there seems to be a gradual increase in the number of poisonous herbs which means more and more drugs have been recognized for their poisonous nature with time.
‘Charaka’ ’ in the 23rd chapter of cikitsasthana has mentioned following ten properties of Vishas, viz – Laghu, Ruksha, Ashu, Vishada, Vyavayi, Tikshna, Vikasi, Sukshma, Ushna and Anirdeshya rasa. ‘Susruta’ in Kalpasthana also reported similar ten properties, but included Avipaki in place of Aniredesya rasa. Acharya Sharangdhar listed eight properties of Vishas they are Vyavayi, Vikasi, Sukshma, Chhedi, Madavaha, Agneya, Prananashaka and Yogavahi.
Importance of Purification of poison
The poisonous plants reported in ancient scriptures of Ayurveda are still being used widely in a number of diseases after processing with proper Shodhana. Ayurvedic physicians successfully employed these drugs after proper Shodhana. The concept of Shodhana was mentioned for the first time in Charaka Samhita in the context of Danti Dravanti Kalpadhyaya. To reduce the ‘Vikasi’ property of Danti root, Charaka mentioned it as ‘Samaskara’. Acharya Vagbhata also mentioned Shodhana of drugs of plant origin in detail, in the context of Bhallataka Rasayana for 'Bhallataka’ (Semicarpus anacardium). It is reported that Aconite (Vatsanabha) purified by cow urine is converted to cardiac stimulant, whereas raw Aconite is cardiac depressant. It is clearly mentioned in ‘Bhava Prakasha’ that the bad/toxic effects attributed to ‘Ashodhita Vishas’(unpurified poisonous substances) are minimized when these are used after being subjected to Shodhana . Hence ‘Vishas’ should be essentially subjected for Shodhana before being used in therapeutics.
General Processing of Poisonous substances before consumption.
On Review of Ayurvedic literature it is observed that
Various Shodhana procedures are mentioned for visha and Upavisha group of drugs.Out of these, following procedures are common for different ‘Vishopavisha’ drugs.
Out of the procedures described above, cow urine and boiling with cow milk are the most common procedures applied for almost all the ‘Vishopavisha’ drugs.
SCHEDULE E (1) of THE DRUGS AND COSMETICS ACT, 1940
Provides the List of poisonous substances under the Ayurvedic, Siddha and Unani System of Medicine, which is as follows :-
A. AYURVEDIC SYSTEM
I Drugs of vegetable origin
II Drugs of Animal Origin .
III Drugs of Mineral Origin
Dos during consumption of visha
Rice prepared with ghee, honey, sugar, wheat is beneficial. Drinks prepared with rock salt, black grapes in cold infusion, staying at cold places, drinking of cold water and following celibacy.
Don’ts during consumption of visha
Bitter, acidic or oily food including curd should be avoided. Donot expose to sun.
Visha Dravya and its Action--On the basis of the action on various components of body, the probable mode of action of a visha dravya has been described in Ayurveda. It produces distress of the body constituents, burning sensation and putrefaction. Vishada guna, does not have any mucous property and doesn’t stop anywhere in the body, passes through all the doshas, resulting in their vitiation. In this way, visha leads to vitiation of all the three doshas and becomes complicated to treat. Vikasi guna breaks the bonding between various dhatus and thereby causes looseness in dhatus (dhatushaithilya), resulting in their improper function. Activity of a visha dravya depends on the dominance of guna possessed by it. For instance, domination of ruksha guna will lead to the vitiation of vata, domination of sukshma guna lead to vitiation of rakta dhatu, as compared to others, while domination of tikshna guna will lead to impairment of three marmas of the body i.e.shira, hridaya and basti and may lead to murchha, sanyasa and other symptoms of marmaghata.
Visha Vis a Vis Madya--Classical texts of Ayurveda attributed ten common gunas to both madya and visha, where the intensity of the Guna of visha is more than that of madya. Study of visha gunas is necessary for its treatment. Since the basis of treatment is samanya-vishesha siddhanta, a drug or diet which is opposite in the properties as that of the disease, should be used for its treatment.