Numerous languages characterize 'social pain', the feelings resulting from social estrangement, with words typically reserved for describing physical pain ('broken heart', 'broken bones') and perhaps for good reason. It has been suggested that, in mammalian species, the social-attachment system borrowed the computations of the pain system to prevent the potentially harmful consequences of social separation. Mounting evidence from the animal lesion and human neuroimaging literatures suggests that physical and social pain overlap in their underlying neural circuitry and computational processes. We review evidence suggesting that the anterior cingulate cortex plays a key role in the physical-social pain overlap. We also suggest that the physical-social pain circuitry might share components of a broader neural alarm system.