In radiation injury, several decades of research support the usage of angiotensin converting enzyme (ACE) inhibitors for mitigation of a range of radiation-induced toxicities including: acute hematopoietic injury (McCart et al., 2019), pneumonitis (Medhora et al., 2012; Gasperetti et al., 2021; Mungunsukh et al., 2021), cardiac fibrosis (van der Veen et al., 2015), optic neuropathy (Kim et al., 2004; Ryu et al., 2007), and nephropathy (Moulder et al., 2007; Fish et al., 2016). Here, ACE is linked to pneumonitis.