The tongue is the primary organ of taste and considered as the mirror that reflects the conditions of the body's internal organs, particularly the organs of digestion and metabolism. The tongue also reflects the overall digestive, nutritive and metabolic conditions of the organism. An ideally healthy tongue will look clean and have a pink colour with no white coating.
In Ayurveda, Acharya Yogaratnakara has mentioned tongue examination as Jiwha Pariksha under Ashtasthana pariksha. Jiwha (Tongue) tells about the Dosha, Agni and Kostha. The tongue is the window to our digestive system. There is a large amount of information that can be learned from this observation, including the health of various bodily systems, toxins within the system, emotional states, and much more.
So, the inspection of the tongue becomes an important starting point in the clinical examination and a careful observation of the state of tongue, its colour, and shape often gives a physician an insight into the current health condition of the patient