The yogi who keeps the tongue upward even for half an instant is free from poisons, diseases, death, old age and so on.

Rasanām ūrdhvagām — the tongue directed upward.Even the simple version of Khecarī (tongue pressing on the roof of the mouth) has benefits.Kṣaṇārdham api — even for half an instant — suggests that the effects are immediate and intense.

Viṣair vimucyate — becomes free from poisons.This siddhi of immunity to toxins appears frequently in Haṭha Yoga texts.It can be interpreted literally (resistance to harmful substances) or symbolically (purification of mental “poisons” such as anger, envy, etc.).

Vyādhi-mṛtyu-jarādibhiḥ — of diseases, death, old age and so on.Khecarī mudrā is considered one of the most powerful practices for longevity and transcendence of bodily limitations.