Introduction: One of the psychiatric disorders in people with diabetes is anxiety. Stress and anxiety affect the glycemic control in many diabetic patients. Furthermore, stressful life events are significantly associated with the poor glycemic control. The effectiveness of saffron on anxiety reduction has been demonstrated in animal samples. Regarding this, the present study aimed to determine the effect of oral capsules of saffron on the anxiety level of the diabetic patients in Zabol, Iran, in 2017.Materials and Methods: This quasi-experimental study was conducted on 50 patients with diabetes mellitus in Zabol. The samples were randomly divided into two groups of intervention and control. The participants’ levels of anxiety were measured using the Spielberger’s Anxiety Inventory. The intervention group received 300 mg saffron capsules; on the other hand, the control group were given placebo capsules. The capsules were daily administered between 12 and 14 p.m. (i.e., after having lunch) for one week. The patients’ anxiety levels were reexamined after a week. The data were analyzed using the SPSS version 22.Results: Prior to the intervention, the mean anxiety levels were 47.98 and 48.62 in the intervention and control groups, respectively. The anxiety scores of the patients did not show statistically significant differences between the two groups (P=0.71). However, at the post-intervention stage, the mean anxiety levels of the intervention and control groups were 30.72 and 49.12, respectively, indicating a statistically significant difference (P=0.001). In addition, the mean anxiety of the patients in the intervention group demonstrated a statistically significant difference between the pre- and post-intervention stages (P=0.001). Nevertheless, the control group showed no significant difference in this regard between the two stages (P=0.07).Conclusions: As the findings of the present study indicated, the oral capsules of saffron were effective in reducing the anxiety in the patients with diabetes. Saffron has been demonstrated to have antispasmodic, painkilling, carmintive, and appetite stimulating effects, which is effective in preventing and treating many diseases. Regarding this, this herb can be used in the management of the anxiety in the diabetic and other patients along with other treatments.