Ayurvedaemphasis the relationship between man & plants throughout the development of human culture. The use of plants for healing purpose is very common in developing countries Medicinal plants are used indiscriminately without knowing their possible adverse effects.Theseeffects are due to the presence of some phytotoxic compound present in the plants. Since immemorial time many poisonous plant are used as a medicine.Butbefore its therapeutic use their purification means shodhanasanskara is mentioned in Samhitas. These shodhana procedures reduce toxicity of these plants and also improvetheir quality. As the action of poison is very fast because of its quality, same quality may be useful while treating the diseases when these plants are used in medicine. So formulations prepared by these poisonous plantare more efficacious and fast acting.