Several plants, fruits and seeds having hallucinogenic properties.

$\Rightarrow$ They have been used for hundreds of years in folk-medicine, religious ceremonies and rituals all over the globe.

When these are taken for a purpose other than medicinal use or in amounts/frequency that impairs one's physical, physiological or psychological functions, it constitutes drug abuse.

E.g Morphine is secondary metabolite obtained from papaver somniferum. acetylation of it produces Heroin.