The definition of ‘patient’ is commonly taken for granted and considered as obvious, but the term is rather underconceptualised in the literature. In this paper, it will be argued that the criterion of suffering can be considered a sufficient criterion for a parent to be considered a secondary patient when their seriously ill child is receiving medical care (i.e. not necessarily the parents themselves) – these parents are sufferers in virtue of the suffering of others. The nature of parental and (...) child health and well-being is clearly relational and bidirectional, thus also a bidirectional and relational integration of parental and paediatric patient care is necessary. A genuine expansion of the concept ‘patient’ to parents, both practically and theoretically, can help to bring awareness to the closely intertwining, interacting and interdependent vulnerabilities of both parties, the potential conflicts of interests involved, and also to demand support and reduce hurdles, for example, in reimbursement by health insurers. Treating parents as patients will (1) help the affected child (the primary patient), as unhealthy and/or mentally unstable parents are likely to negatively influence a child's treatment and (2) prevent the parents (the secondary patients) from becoming primary patients themselves due to their suffering because of their child's illness. (shrink)