The strychnine tree (Strychnos nux-vomica L.) also known as nux vomica, poison nut, semen strychnos and quaker buttons, is a deciduous tree native to India, southeast Asia. It is a medium-sized tree in the family Loganiaceae that grows in open habitats.

Strychnos has not been proven effective for the treatment of any illness. Since the seeds contain strychnine poison, conventional doctors do not recommend it as a medicine.
In the Indian Unani system of medicine, "hudar" is a mixture containing Strychnos nux-vomica and used to elevate blood pressure.The seeds are first immersed in water for 5 days, in milk for 2 days followed by their boiling in milk.[5] In India, the quality/toxicity of traditional medical crude and processed Strychnos seeds can be controlled by examining the toxic alkaloids using established HPLC methods and/or HPLC-UV methods.