The Native American dudes in the image above are vomiting due to a drink made from Ilex vomitoria — aka yaupon holly. Despite the name, Ilex vomitoria, this ingredient does not cause the vomiting; you can drink the tea made from these leaves to satisfy your caffeine needs and the tea is sold online. The ursolic acid found in the tea strengthens skeletal muscle and; of course, caffeine is a stimulant. Vomiting may have allowed them to drink more.
My novel involves another recipe. A recipe for a genetic memory drug and my fictional fertility cult wishes to improve this drug. The reason I mention the Black Drink made from yaupon holly leaves because it carries a secret ingredient and my recipe thrives on secrecy.
The image comes from Wikipedia which offers the following description: