Gamboge

藤黄 Téng huáng (藤黃) Gamboge saffron/mustard yellow herbal colour used to dye Buddhist monks’ robes, normally comes from Garcinia tree which is also where the delicious mangosteen fruit comes from!  A hole is made in the tree bark and the sticky yellow resin used to make the colour flows out.
The best Gamboge saffron/mustard yellow was historically from Vietnam and so also called Yue Huang 月黄 (Vietnam Yellow), though also produced by Cambodia and Thailand.
Gamboge is also a traditional ingredient in Chinese medicine – but for external use only as it is poisonous and must not be taken internally.