Which plant's orange sap is used to treat warts?

The plant whose orange sap is traditionally used to treat warts is greater celandine.

Greater celandine (Chelidonium majus) produces a bright yellow-orange latex when its stem or leaves are broken. Folk medicine in parts of Europe has applied this acrid sap directly to warts, which are viral growths caused by human papillomaviruses. The plant’s latex contains alkaloids and enzymes that may irritate or damage tissue around the wart.

This is a traditional remedy, not proof of safe or reliable treatment. Greater celandine is poisonous in moderate doses, and oral preparations have been associated with liver injury. It should not be confused with lesser celandine, a buttercup relative, or bloodroot, another plant with similarly colored sap and historical medicinal use.

The name “celandine” has also encouraged confusion with plants used for eye remedies. In modern medicine, wart treatments such as salicylic acid and cryotherapy are more established; raw greater celandine latex can burn healthy skin.