In a recent commentary (Nature 309, 400; 1984) John Maddox suggested that the study of psychological effects on immunologic functions - 'psychoimmunology' - was somewhat premature. Specifically, he argued that while the concept of a link between the central nervous system and the immune system was easily accepted, there was a paucity of data of a mechanistic nature to explain the evidence that the 'mind' can control immune responses. He doubted, therefore, whether enough is known to sustain the hope that psychoimmunology was explainable. Much evidence to the contrary was apparent in the proceedings of three recent meetings on the subject which has been variously termed neuroimmunomodulation, psychoimmunology and neuroimmunoendocrinology. © 1985.