Informal caregiving is a potentially attractive alternative to formal care but may entail health costs for the caregiver. We examine the mental and physical health impact of providing informal care and disentangle the caregiving effect – the effect of caring for someone in need – from the family effect – the effect of caring about someone in need. We account for the main sources of endogeneity in the caregiving decision using Arellano-Bond difference GMM models. We use four waves (2010–2013) of panel data from the Dutch Study on Transitions in Employment, Ability and Motivation (STREAM). We find that caregiving harms the mental health of caregivers the effect is more prominent for spousal caregivers. On top of this, a negative health shock of a family member also has a direct negative effect on mental health, providing evidence of a family effect. Our findings thus highlight that the total effect of having a sick relative may be underestimated when the family effect is not adequately accounted for. As the caregiving effect differs substantially between various types of caregivers, policies to cushion these effects should specifically target those subgroups of caregivers that carry the largest burden of informal caregiving.