Background: Primary palmar hyperhidrosis (PH) often develops throughout infancy or adolescence and lasts the entirety of one's life. Although its cause is uncertain, it is believed to be caused by localised sympathetic hyperactivity on otherwise healthy eccrine sweat glands, which is typically brought on by emotional or temperature stimulus. Objective: To evaluate the therapeutic efficacy, tolerability and side effects of the low concentration (1%) versus high concentration of aluminium chloride hexahydrate (20%) iontophoresis for primary palmar hyperhidrosis. Patients and Methods: Thirty patients of both genders who established diagnosis of primary palmar hyperhidrosis with age ranged 10-30 years were selected randomly from dermatology outpatient clinic of Ain Shams General Hospital, Cairo, Egypt. The included subjects were randomly distributed into two equal groups; Group (A) consisted of 15 patients (9 females and 6 males) with palmar hyperhidrosis were treated with iontophoresis of low concentration 1% aluminum chloride for 3 days per week for 4 weeks. Group (B) consisted of 15 patients (8 females and 7 males) were treated with iontophoresis of high concentration 20% of aluminium chloride hexahydrate at the same time. Results: Both groups of the study showed a significant decrease in hyperhidrosis from the 3^rd day until the 4^th week post-treatment (p < 0.05) throughout the follow-up period. However, comparing between both groups revealed that improvement in group B was slightly better than group A (P < 0.04), but with more side effects like dermatitis and low endurance, some patients might stop the treatment sessions. Conclusion: application of low concentration iontophoresis; 1% of aluminium chloride hexahydrate compared to a high concentration approach (20%) results in a significant reduction in the rate of palmar sweating with extended endurance and no skin irritation.