Last verified: April 2026
Dravyaguna — Classical Pharmacology
Dravyaguna is the Ayurvedic science of pharmacology — the systematic study of every medicinal substance through five evaluation parameters: Rasa (taste), Guna (qualities), Virya (potency), Vipaka (post-digestive effect), and Prabhava (special potency). Together these parameters predict therapeutic action across all Dosha, Dhatu, and Srotas.
The four herb evaluation parameters
Every substance in Ayurvedic pharmacology is assessed through four parameters that together completely characterise its therapeutic action: Rasa (taste — the immediate effect experienced by the tongue and mouth, reflecting elemental composition); Guna (qualities — the 20 physical properties in 10 opposing pairs that describe how the substance behaves in the body); Virya (potency — essentially whether the net effect is heating or cooling, which determines which Dosha is primarily affected); Vipaka (post-digestive taste — the effect registered after complete metabolic processing, determining long-term Dhatu action). These four, taken together, predict approximately 80% of an herb's therapeutic behaviour. The remaining 20% is governed by Prabhava (special potency — effects that exceed what the four parameters would predict).
The 20 Guna — 10 opposing pairs
Charaka Samhita, Sutrasthana 1 documents 20 qualities in 10 pairs — each pair consisting of opposing properties. The fundamental principle: like increases like (Samanya Vriddhi), and opposites reduce each other (Vishesh Hani). Every therapeutic action works through this principle — a cooling herb reduces the hot quality of excess Pitta; a heavy herb reduces the light quality of excess Vata; a drying herb reduces the oily quality of excess Kapha.
| Guna (Heavy) | Meaning | Opposite (Light) | Meaning | Dosha effects (first/second) |
|---|---|---|---|---|
| Guru | Heavy | Laghu | Light | Increases Kapha, reduces Vata; decreases Pitta | Increases Vata, reduces Kapha |
| Manda | Slow/dull | Tikshna | Sharp/penetrating | Reduces Pitta; calming | Increases Pitta; penetrating to channels |
| Sheeta | Cold | Ushna | Hot | Reduces Pitta, increases Vata-Kapha | Reduces Vata-Kapha, increases Pitta |
| Snigdha | Unctuous/oily | Ruksha | Dry | Nourishes, lubricates, reduces Vata | Drying, absorbs, reduces Kapha |
| Shlakshna | Smooth | Khara | Rough | Calming, healing | Scraping, cleansing channels |
| Sandra | Dense/solid | Drava | Liquid/flowing | Stabilising, building | Moving, dissolving |
| Mridu | Soft | Kathina | Hard | Calming, nourishing | Strengthening, channel-opening |
| Sthira | Static/stable | Chala | Mobile/unstable | Grounding, healing | Stimulating, moving |
| Sukshma | Subtle/fine | Sthula | Gross/large | Penetrates fine channels | Acts on gross channels |
| Vishada | Clear/non-slimy | Picchila | Slimy/sticky | Cleansing, light | Nourishing, channel-coating |
The six Rasa (Tastes) and their elemental basis
Each of the six tastes is composed of two Panchamahabhuta elements, producing predictable Dosha effects. Full documentation: Six Tastes page. Key principle: Virya (potency) often overrides Rasa in therapeutic effect — an herb may taste sweet (which would normally be Kapha-increasing) but have Ushna Virya (hot potency) making it net Kapha-reducing. This is why Rasa alone is insufficient for herb assessment.
Karma — the 40+ classical pharmacological actions
Karma describes what the herb does — the specific physiological action produced in the body's channels and tissues. The following are the primary documented Karma in classical pharmacology:
| Karma | Definition and examples | Category |
|---|---|---|
| Deepana | Kindles Agni without digesting Ama — e.g. Shunthi, Maricha | Digestive fire |
| Pachana | Digests Ama without kindling Agni — e.g. Guduchi, Musta | Ama digestion |
| Anulomana | Promotes downward movement of Vata — e.g. Haritaki, Triphala | Peristalsis |
| Sramsana | Mild laxative — softens and moves stool — e.g. Trivrit (mild dose) | Mild purgation |
| Bhedana | Strong purgative, breaks apart obstruction — e.g. Trivrit (full dose) | Strong purgation |
| Rechana | Virechana-grade purgation — e.g. Trivrit, Eranda Taila | Therapeutic purgation |
| Grahi | Absorbs excess fluid, firms stool — e.g. Bilva, Lodhra | Astringent-absorbent |
| Stambhana | Stops flow — haemostatic, antidiarrhoeal — e.g. Ashoka | Flow-stopping |
| Lekhana | Scraping — removes accumulated Kapha/Meda from channels — e.g. Guggulu, Trikatu | Fat/Kapha reducing |
| Brimhana | Nourishing — builds all Dhatu — e.g. Ashwagandha, Shatavari | Tissue nourishing |
| Balya | Strengthening — increases Bala (general strength) — e.g. Bala, Ashwagandha | Strengthening |
| Jivaniya | Life-promoting, Ojas-building — e.g. Shatavari, Amalaki | Life-sustaining |
| Medhya | Cognitive-enhancing — e.g. Brahmi, Shankhpushpi, Guduchi | Cognitive |
| Hridya | Cardiac-beneficial — e.g. Arjuna, Shatavari | Cardiac |
| Keshya | Hair-nourishing — e.g. Bhringaraj, Amalaki | Hair |
| Chakshushya | Eye-beneficial — e.g. Triphala, Yastimadhu | Ophthalmic |
| Varnya | Complexion-improving — e.g. Haridra, Shatavari | Complexion |
| Krimighna | Antimicrobial/antiparasitic — e.g. Vidanga, Neem, Kutki | Antimicrobial |
| Vishagna | Antitoxic — e.g. Guduchi, Jatamansi, Tulsi | Antitoxic |
| Rasayana | Rejuvenating all Dhatu — e.g. Amalaki, Ashwagandha, Shilajit | Rejuvenation |