['Oral administration of zinc or bovine whey-derived growth factor extract (WGFE) is known to reduce intestinal permeability and ameliorate methotrexate (MTX)-induced mucositis, respectively.', 'We examined the effects of zinc, WGFE, and zinc plus WGFE on gut damage in MTX-treated rats.', 'Rats (n = 16/group) were fed zinc (1000 mg/kg diet), WGFE (32 mg/kg diet), zinc plus WGFE, or control (10 mg Zn/kg diet) diets for 7 d and then injected subcutaneously with MTX (2.5 mg/kg) for 3 d to induce gut damage. Gut histology and intestinal permeability were assessed.', 'The Zn+WGFE diet was associated with both reduced gut damage on day 5 and enhanced recovery on day 7. The WGFE diet ameliorated gut damage, whereas the Zn and Zn+WGFE diets enhanced repair. Gut metallothionein and tissue zinc concentrations were significantly (P < 0.01) higher with Zn and Zn+WGFE on days 5 and 7 than without zinc supplementation. The Zn and Zn+WGFE diets significantly (P < 0.05) decreased gut permeability on days 3-4 compared with the control diet. Intestinal permeability was significantly (P < 0.05) increased on days 5-6. On days 6-7, only the WGFE diet improved gut permeability (by 80%) compared with the control diet.'] Does dietary supplementation with zinc and a growth factor extract derived from bovine cheese whey improve methotrexate-damaged rat intestine?