Mondjo (in English "Devil's Trumpet") is the common name with which the Ba-Ronga of South Africa call the Datura fastuosa, a poisonous plant that has a very high concentration of tropical alkaloids.
This plant, in the Ba-Ronga tribes, represents a real fundamental tool for the correct maintenance of order and justice in the village. In fact, it is the protagonist of the ordeals through which the village leaders highlight, before all those present, the guilt of some individuals for crimes such as witchcraft or adultery.
Specifically, a small dose of a complex potion prepared with Mondjo's poison is given together with other particular ingredients, such as the fat or dust of the bones of a leper who has been dead for some time.
Once tested its effectiveness on Moudlayi, the head of all the sorcerers, the accused men and women are gathered near a lake and each one is given a sip of the potion. After that they are made to sit in the midday sun and forced to remain completely still, without moving even to scratch. When one of the accused begins to scratch and fidget, the Moudlayi hands him the large feather he brings with him during the ritual dances that accompany the ordeal. The individual concerned, in the grip of the effects of the poison, will prove unable to grasp it, thus highlighting his guilt.
At the end of this phase, everyone else is ordered to run to wash in the lake. Here too, however, those who fall or stumble will be considered baloyi (guilty) as much as the first ones.
Once all the "criminals" have been identified, they are interrogated, but only after allowing them to regain their ability to speak, through an infusion of herbs (tchéké) and the friction of some particular leaves on the cheeks. During the interrogation, the perpetrators will admit their crimes, on the basis of which they will be reprimanded, flogged or even banished from the village.