In addition to induction of metabolic acidosis (Table 1), excess dietary ammonium attenuates a key facet of Tlr4‐dependent innate immune to UPEC‐UTI and thereby markedly exacerbates cystitis (Figures 2 and 3) and pyelonephritis (Figure 1) in C3H mice prone to VUR, (Purkerson et al., 2020), which in turn triggers CD dysfunction and a urine concentration defect (Table 3). Here, TLR4 is linked to cystitis.