Introduction: Obesity is today considered as one of the problems of human society. Obesity is a predisposing factor for chronic diseases such as cardiovascular disease, diabetes, hyperlipidemia and hormonal disorders. In addition to physiological problems, obesity impairs psychosocial dimensions and reduces quality of life. Ghrelin is an appetizing peptide that plays a key role in the regulation of energy balance. According to anti-appetite effects of cumin, the aim of this study is to evaluate the effect of aqueous extract of caraway seeds on the ghrelin hormone in male rats. Method: In this experimental study, 32 adult male Wistar rats were divided into 4 groups of 8 animals, including control and experiment receiving cumin (at concentrations of 60 and 90 mg/kg). Cumin was administered to animals by gavage. Fifty-seven days after the start of the experiment, the animals were weighed and blood samples have been taken out of the heart and serum concentrations of ghrelin hormone were measured. Results were analyzed with ANOVA test and Duncan test at a significance level of 05/0 p≤. Results: In comparing different doses of aqueous extract of black cumin seeds, the most evident effects of reduced serum concentrations of ghrelin hormone and weight loss were related to the extract group at dose mg / kg90. Conclusion: Because of its anti-anorexia, cumin reduces hormone ghrelin secretion and loss of appetite in rats, resulting in weight loss and prevents weight gain.