Karma refers to pharmacological activity of a drug. Medicinal activity of a drug is based partly on basis property (gunas) and partly on basis of specific action (prabahva). In Ayurveda, drugs have been classified according to pharmacological action. If comparative study is done on modes of classification of drugs in Ayurveda and Allopathic, it can be concluded that modern drug classification is similar to ancient one.
Classification of drugs in Ayurveda
In Ayurveda, the medicinal herbs have been classified on various patterns:
- Classification based on action on three biological humours (vata, pitta and kapha).
- Classification based on action on medicinal activity like artvajanana (emmenagouge).
- Classification according to groups like Salasargana.
Classification based on action on medicinal activity seems to be more scientific
A. Drugs acting on digestive system
- Anulomna (Carminative): They help in expulsion of gas from the stomach by relaxing the cardiac sphincter. They stimulate intestinal motility and induce a sensation of warmth in the abdomen. Ayurvedic formulations acting on the digestive system includes certain aromatic and volatile oil containing medicinal herbs like Jatiphala (Myristica officinalis) or Dhanyaka (Foencilium vulgare). Hingu (Ferula foetida) is one of the best carminatives.
- Arshoghana: Drugs used in the treatment of hemorrhoids or piles. Surana (Amorphophallus campanulatus) is common example.
- Atisarghana (Antidiarrhoeal): They prevent diarrhoea. Majuphala (Quercus infectoria) represents this class. The drug contains tannins having astringent action on the intestine.
- Chardinigrhana (Anti emetics): These prevent vomiting. Ushira (Vetiver zizionides) is typical example.
- Dipana (Appetizer): A drug used to promote appetite. Examples include Chirata (Swertia chirata). The drugs are highly bitter and they stimulate the taste buds in the tongue. They act reflexly to increase secretion of saliva and gastric juices.
- Kriminghana (Anthelmintic): The drug used in treatment of worm infestation. The anthelmintics which help in expulsion of worms are known as vermifuges and which kills the worm are known as vermicidal. Palasha (Butea monosperma), Vidanga (Embelia ribes) are reputed anthelmintics.
- Lalasravavridhikara (Sialagouge): These are the drugs which stimulate the flow of saliva. Akarakarambha (Anacyclus pyrethrum) is example.
- Pachana (Digestive): A drug used to correct the digestive power. Bitter drugs are again used for this activity. Nagarmotha (Cyperus rotundus) is widely used by in Ayurvedic prescriptions for digestive action. Some drugs like Raktachitraka (Plumbago rosea) and Chitraka (P. zeylanicum) have dual activity viz appetizer as well as digestive.
- Sranshana (Laxatives or aperients): These groups of drug lubricate the intestinal tract and soften the faeces. Aragbhada (Cassia fistula) is typical example.
- Bhedana (Purgatives): These groups of drugs usually irritate the small intestine and help in passage of feaces. Eranda (Ricinus communis) represents this group.
- Rechana (Drastic purgatives): These drugs irritate the small and large intestine resulting in griping, dehydration, and copious watery stool. Giriparpata (Podophyllum hexandrum) is common example of drastic purgative.
- Purishasangrheneya (Grahi): The drugs which are used in treating diarrhoea, dysentery or malabsorption. Because of there astringency, these drugs check excess flow of fluid.
- Trishna-nigrahna: These drugs are used for suppressing excess thirst. Parpata (Fumaria officinalis) and Dhankya (Coriander sativum) are included in this group. Shadaga-paniya is Ayurvedic formulation for quenching thirst in fevers.
- Vamaka (Emetics): This group of drugs induces vomiting. Madanphala (Randia dumetorum) is standard Ayurvedic emetic. Antamoola (Tylophora asthmatica) is emetic in high doses. Therapeutically emetics are rarely used in modern system of medicine.
B. Drugs acting on respiratory system
- Kaphanissaraka (Expectorant): These drugs help in expelling the secretions from upper respiratory tract. Talishapatra (Taxus baccata) is good example.
- Kashara (Antitussives or cough suppressants): These drugs are used to suppress cough. Kantkari (Solanum xanthocarpum) and Brahati (Solanum indicum) are typical examples.
- Svashara (Bronchodilators or bronchial antispasmodics): These drugs relax the spasm of bronchi and are thus useful in treating bronchial asthma. Datura (Datura stramonium) and Bharangi (Clerodendron serratum) are examples of bronchodilators.
C. Drugs acting on heart
- Hrddya (Cardiac tonics): These drugs stimulate the cardiac muscle. Tilapushpi (Digialis purpurea) and Vanaplandu (Urginea indica) are included in this category.
- Shothara (Anti-inflammatory): These drugs help in curing edema. Dashmoola drugs are included in this category.
D. Drugs acting on circulatory system
- Raktaprasadana (Alterative): These groups of drugs increase blood supply to a skin. Gorakhmundi (Sphearahthus indicus) is example.
- Raktaskandana (Styptics): These drugs check local bleeding. Mocharasa is typical example.
E. Drugs acting on nervous system
- Nadi balya (Nevine): These groups of drugs increase the action of the nerves and are also known as nervine tonics. Ashwagandha (Withania somnifera) and Kiwanch (Mucuna prurita) are examples.
- Nidrajanana (Hypnotics): These drugs induce sleep and are used in curing insomnia and insanity. Jatamansi (Nardostachys jatamansi) is good example.
F. Drugs acting on kidney
- Ashamrighna (Lithontriptics): These help in dissolving kidney stones. Varuna (Cratevea nurvala) is included in this category.
- Mutrala (Diuretics): These groups of drugs produce increased urinary flow. Gokshura (Tribulus terresteris) and Poonarnava (Boerrhavia diffusa) are diuretics. They are used in treating edema.
- Mutrasangheneya: These acts reverse to diuretics. They suppress the increased urinary flow. Vimbi (Coccinia indica) is familiar example.
G: Miscellaneous drugs
- Ashukari: The drugs which instantaneously enter the blood circulation.
- Paramathi: The drugs which clears the channel of circulation.
- Pittasraka (Cholagouges): Drugs which are believed to increase the secretion of bile.
- Rasayana: These groups of drugs prolong the life by tonic action on the body. Amalaki (Phyllanthus emblica) is example.
- Sandhaneya: These drugs are used for promoting healing of fractures. Asthishrikhala (Cissus quadangularis) is example.
- Stanyajanana (Galactagouge): These drugs stimulate the flow of milk. Jiraka is example.
- Vajikarna (Aphrodiascs): These groups of drug promote appetite for sex. Some drugs act by increasing the sperm count and are known as spermipiotics. Safed musli (Asparagus adscendens) is good example.
- Vidahi: The drugs which affect the function of the digestive system. Sasharapa (Brassica nigra) is example.
- Vyavayi: The drugs which have acute affect on the body. Narcotic poisons can be included in this category.
- Ykritautejjaka (Choleretics): The drugs having stimulating action on the liver. Kakamachi (Solanum nigrum) and Sharpuknka (Tephrosia purpruea) are common examples.