What is the ruling on drinking civet coffee, which is extracted from the droppings of the civet animal? And what must one do if they drank it unknowingly of its prohibition?

If coffee beans emerge solid from an animal and have not absorbed the impurity, it is permissible to use them after washing them. This is an analogy to barley that emerges solid from animal dung and is eaten after being washed, and to date pits and pebbles that exit the belly, of which only their outer surface becomes impure.

However, if the beans have changed and absorbed the impurity, it is not permissible to drink coffee made from them. The pure substance is that which retains its solidity as it is, such that if it were planted, it would sprout. Its outer surface must be washed due to contact with impurity. But if its solidity is gone, then it is impure.