BACKGROUND: Nutritional complications following surgery for morbid obesity include both vitamin and mineral deficiency. Severe cases of zinc deficiency can lead to alopecia, diarrhea, emotional disorders, weight loss, intercurrent infection, bullous-pustular dermatitis and hypogonadism in males. Hair loss may occur after vertical gastroplasty (VG). METHODS: Diffuse hair loss occurred in 47 out of 130 patients who underwent VG. All patients had been routinely advised to take a multivitamin supplement, but 47 developed hair loss despite taking the supplement. These patients were then prescribed Zinc Sulphate 200 mg three times a day. There was no alteration in the vitamin supplementation. RESULTS: Arrest of hair loss and regrowth occurred in all patients. However, five patients reported recurrence of hair loss after stopping zinc. This loss was reversed within 6 months of recommencing zinc 600 mg daily. Ten control patients had no hair loss after gastrointestinal surgery. CONCLUSION: Significant hair loss occurred in about one-third of patients after VG, and was reversed by zinc supplementation.