Inclusion criteria:
Functional constipation confirmed by ROME 4 criteria
Defecation twice a week or less;
History of stool retention;
history of painful defecation;
History of large stool diameter;
History of large stool mass in rectum;
Exclusion criteria:
Patients with stractural causes of constipation such as celiac disease; pseudo-obstruction; hypothyroidism; spina bifida, anorectal malformation; hirschsprung's disease;
Patients with chronic illness who need special care such as: renal stone; sickle cell anemia; cerebral palsy; hepatitis; hematologic diseases; gastrointestinal bleeding; recurrent fever or fever without locolized sign; Pregnanccy; History of gastrointestinal tract surgery exept for appendectomy; History of allergy or Drug sensitivity; autism; major psychotic disorder such as bipolar disorder; schizophrenia;
Children who had experienced physical abuse and sexual abuse;
Use of medication such as Metoclopramide, Erythromycin, Bethanechol, CoAmoxiclav, Azithromycin, Domperidone, Amitriptyline, Hyoscyamine, Clonidine, Baclofen, Dicyclomine, Scopolamine;
Weight loss more than five percent in the past three monthes;
Using drugs that have an unknown effect on the gastrointestinal tract