Visha means poison. Visha Chikilsa or Agada Tantra involves the treatment of diseases caused by the impact of poisons and toxins, such as spoilt food, animal, reptile and insect bites, poisonous minerals and unsuitable food combinations, on the body. It is equivalent to toxicology in modern medicine.

Visha Chikilsa describes the action of harmful elements on the body functions and how it can destroy the body tissues. Specific antidotes for poisons were prescribed for nullifying its effects. Ancient texts such as Charaka Samhitha, Susrutha Samhitha and Ashtanga Samgraha offer exhaustive information on this branch of Ayurveda.