It has long been recognized that chronic brucellosis may present as a psychoneurotic illness, and this is well emphasized by Spink (1963) in Cecil and Loeb's Textbook of Medicine. However, presentation in the form of a psychosis is rare, and this is not mentioned in Spink's article, nor in a standard psychiatric textbook such as Mayer-Gross, Slater and Roth (1954). Dalrymple-Champneys (1960) described a series of 1,500 cases of brucellosis; only two of his patients had delusions and hallucinations. Hobbs (1931) described the case of a woman of 56 who developed delusions of persecution and believed her food to be poisoned. This latter symptom was also shown by one of the patients in Dalrymple-Champneys' series, and the same complaint occurred in my patient. Although a very rare cause of paranoid illness, the recognition of brucellosis is important so that appropriate treatment can be instituted.