A Dietary Supplement Supporting the Resolution of Acute Diarrhea in Dogs

(1) Background: Acute diarrhea is a frequent clinical manifestation in dogs, often involving dysbiosis and mucosal barrier impairment. This study evaluated the efficacy of Florentero Complex® (Candioli S.r.l.), a multi-targeted dietary supplement combining probiotics, prebiotics, and antioxidant components, in supporting the recovery of dogs with acute diarrhea. (2) Methods: In a randomized, controlled trial, 28 client-owned dogs presenting with acute diarrhea for 3–4 days were assigned to either a Treated Group (TRT: standard commercial diet plus supplement) or a Control Group (CTR: standard commercial diet alone) for 7 days. Daily defecation frequency (nDEF), fecal score (FS), and inflammatory markers (fecal cytology and C-reactive protein) were monitored throughout the study. (3) Results: Both groups showed a reduction in nDEF over time, with no significant difference observed between groups. However, a significant intergroup difference in FS was observed, with the supplemented dogs showing a faster and more pronounced improvement in stool consistency than the CTR. Fecal cytology and serum CRP levels also showed a trend toward reduced inflammation in the TRT group. (4) Conclusions: Florentero Complex® appears to provide nutritional support that improves clinical signs and stool quality beyond standard dietary management alone.