Background: Burns are a major cause of stress, and afterwards, many patients suffer from anxiety, depression, and insomnia. Also, the levels of serum antioxidants increase after burns, which causes problems in patients. It has been observed that Melissa officinalis L. can increase serum antioxidant levels and improve mood and sleep quality. Methods: Thirty-six patients who were admitted to Shahid Motahari Burn Hospital were selected. Patients in the control group consumed black tea, and those in the experimental group received Melissa tea. The serum levels of antioxidants were measured using spectrophotometry once before the intervention and at 20 days after the intervention. Depression, anxiety, and insomnia levels were each measured by the Beck, Kettles, and Petersburg questionnaires, respectively. Results: In the study group, the percentages of those experiencing anxiety (P value: 0.023) and depression (P value: 0.002) were significantly less than those of the control group. Also, sleep quality in the experimental group taking Melissa tea increased significantly (P value: 0.031). However, the mean serum antioxidant levels were not significantly different between the control and experimental groups (P value: 0.96). Conclusions: Melissa officinalis L. can significantly reduce anxiety and depression and improve sleep quality. Therefore, its consumption may be useful for burn patients as a daily drink. However, the effects of Melissa on increasing serum antioxidants needs further investigation.