‘Whack’ is a new psychoactive substance available until recently in ‘head shops’. It contains two active constituents, 4-fluorotropacocaine and desoxypipradrol. We present two case reports of subjects who developed acute psychotic states after using Whack. Both individuals displayed similar affective and anxiety symptoms in the presence of significant psychotic symptoms. Both required inpatient treatment but displayed a good treatment response to atypical antipsychotic agents. To our knowledge, this is the first published case series relating to this psychoactive substance.