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Background: Ayurvedic pharmacology explains the action (karma) of a drug through five properties: rasa (taste), guna (quality), virya (potency), vipaka (post-digestive effect) and prabhava (specific action). These constructs form the conceptual basis of drug selection and are increasingly examined using modern pharmacological ideas. Objective: To review the classical definitions and hierarchy of the five properties, the relation between taste and action, and recent biological correlates such as extraoral taste receptors, gut microbiota and bioavailability enhancement. Methods: Classical texts were studied in translation. PubMed was searched in November 2026 for papers on rasa, guna, virya, vipaka, prabhava and Ayurvedic pharmacology. Results: Rasa is the property directly perceived and from which the others are inferred. A statistical analysis of 183 plants confirmed a significant correspondence between predominant taste and reported action. Extraoral taste receptors and gut microbial metabolism have been proposed as biological correlates of rasa and vipaka, and Ayurvedic bio-enhancers are considered to correspond to the modern concept of bioavailability enhancement. Recent work proposes to reinterpret modern drug actions through guna. Conclusion: The five-property scheme provides a coherent and partly testable pharmacology. The strongest evidence relates to taste and action. Other relationships remain hypotheses that should be examined using prospectively defined tests.