Due to its bitter taste and toxic effect, biologists believe caffeine's purpose in plants is to act as a natural pesticide.
N'ezie, n'ihi uto ilu caffeine na nsị na-egbu egbu, ndị ọkà mmụta ihe banyere ndụ kwenyere na ebumnuche ya na osisi bụ ka ọ bụrụ ọgwụ na-egbu ahụhụ.