What is the ruling on chewing (or as they call it, storing) Qat, or trading it?

It has been previously explained that the ruling on khat is that the preponderant opinion is its prohibition, due to the harms resulting from its consumption. If its prohibition is established, then trading in it, whether buying or selling, becomes forbidden. This is because the Shari'ah has ruled that if something is proven to be forbidden, its price is also forbidden, as the Prophet, peace and blessings be upon him, said: "And indeed, when Allah forbids a people from eating something, He forbids them its price."