Objective To observe the clinical efficacy of cucumber on preventing chapped lips and oral cavity ulcer caused by fasting after surgery.Methods A total of 124 fasting patients were randomly divided into experimental group and control group on average.The control group during the period of fasting were painted lips or gargled with warm boiling water or mineral syrup while the experimental group during the period of fasting were laid with cucumber slices or gargled cucumber juice.The incidence of chapped lips and oral cavity ulcer during the fasting period in two groups had been compared.Results The incidence rate of chapped lips and oral cavity ulcer in the experimental group was 4.84%, which was lower than that in the control group(43.55%) with statistical significance (χ2 =90.26,P<0.01).The degree of chapped lips and oral cavity ulcer in the experimental group was lower than that in the control group as well.Conclusions Utilization of cucumber for fasting patients is effective to prevent chapped lips and oral cavity ulcer.