No previous studies have evaluated an oral health programme, before swallowing therapy, in patients with stroke and dysphagia in Taiwan. This randomised controlled trial evaluated the effect of an oral health programme (i.e., sputum assessment, Bass method-based tooth brushing, and tooth coating with fluoride toothpaste) before swallowing therapy. Sixty-six patients with stroke (23 female, 43 male) in our rehabilitation ward, who underwent nasogastric tube insertion, were assigned randomly to an oral care group (n = 33) and a control group (n = 33). Demographic data, oral health assessment, Functional Oral Intake Scale (FOIS) scores, Mini-Nutritional Assessment-Short Form (MNA-SF) scores, and nasogastric tube removal rates were compared between groups. We evaluated outcomes using generalised estimating equation analysis. Three weeks post-implementation, the oral care group had significant oral health improvements relative to the control group (95% CI =−2.69 to −1.25, Wald χ² = 29.02, p < 0.001). There was no difference in the FOIS (95% CI = −0.16 to 0.89, Wald χ² = 1.86, p > 0.05), MNA-SF (95% CI =−0.35 to 0.53, Wald χ² =−0.17, p > 0.05), and nasogastric tube removal (p > 0.05) between groups. The oral care group had a higher, but non-significant FOIS score (3.94 vs 3.52) (p > 0.05). Routine oral health programmes implemented during stroke rehabilitation in patients with dysphagia may promote oral health and maintain oral intake.