Patients with no improvement or with exacerbations in diarrhea, hematochezia, and UC-related laboratory indicators (e.g., C-reactive protein, white blood cell count, hemoglobin) after single FMT (Step 1) were considered for the “step-up FMT strategy” (Figure 1) described in our previous study [17]. Here, CRP is linked to Hematochezia.