There is no fastest laxative food or medicine for diabetic patients with constipation. Patients can eat more foods rich in fiber as appropriate, such as bananas, cabbage and so on. At the same time can also be under the guidance of the doctor to apply drugs such as Keserol for treatment, for promoting defecation has some help. 1. Dietary adjustments: patients should increase water intake, increase the intake of vitamin and fiber-rich foods, such as bananas, spinach, fungus, cabbage and so on. 2. Medication: For patients with serious conditions, laxatives such as Keserol can also be applied under the guidance of a doctor for treatment. The safety of such drugs is relatively high, and generally does not affect diabetes. Due to the different conditions of the patients and their different physiques, it is important to consult a doctor as early as possible to confirm the diagnosis. The corresponding dietary and medication regimen must be in accordance with the doctor’s instructions, and should not be used arbitrarily.