Zinc is an essential microelement, and its deficit causes various diseases and symptoms. In adults, especially in elderly individuals, zinc shortage can cause symptoms such as taste disorder, dermatitis, and susceptibility to infection. In children, zinc deficiency can lead to growth retardation. In 2017, the indication for zinc acetate dihydrate (NOBELZIN ® ) was expanded from Wilson's disease to include hypozincemia, leading to wider use of zinc acetate dihydrate. At five years after this broadening of use, we conducted a post-marketing study (PMS) to investigate the utilization, safety, and effectiveness of zinc acetate dihydrate. Over 52 weeks, the overall incidence of adverse drug reactions (ADRs) was 9.4% (87/928). The most common ADR was copper deficiency (2.4%), followed by nausea (1.4%). Among 928 patients, 19 (2%) developed serious ADRs. Of the patients with copper deficiency, 92% were >65 years of age, and all had comorbidities at baseline. Physicians evaluated the effectiveness of zinc acetate dihydrate using three categories: "effective", "not effective", and "indeterminate". The overall efficacy rate was 83.0%. The average serum zinc levels were elevated from 50-60 μg/dL to >90 μg/dL within 12 weeks, and were maintained up to 52 weeks after administration. Among the symptomatic sub-categories, the efficacy rate was highest in pressure ulcer (96.2%; 25/26), followed by in stomatitis (87.5%; 42/48), and taste disorder (87.4%; 181/207). Among pediatric patients with developmental symptoms, an efficacy rate of 66% was achieved. In conclusion, zinc acetate dihydrate has been safely used, and has produced beneficial effects on various diseases and symptoms.