Saponin
From Memory Alpha, the free Star Trek reference
Saponin is a plant product that can sometimes be found in the form of a poison. A substance from the thorns of the Gamma Trianguli VI pod plant encountered in 2267 was similar to saponin, but 1,000 times stronger.
The effects of the pod plant's poison on Spock could be countered with a very high dose of Masiform-D, which had previously been employed against saponin. (TOS: "The Apple")
