Obesity is becoming a major worldwide health problem associated with a number of diseases. Serotonin (5-HT) is a biogenic neurotransmitter with a well-defined network in the central and peripheral nervous system and plays an important role in the regulation of feeding behavior. Studies revealed that high levels of serotonin are associated with reduced energy intake and its level and function is dependent on the availability of its precursor, tryptophan. Several synthetic serotonin agonists are available in the market to reduce body weight but many of these synthetic drugs were found to have certain side effects. Therefore, there is a great need to search for more economical natural serotonin agonists. Ginseng is a traditional Chinese medicinal herb known for many of its beneficial effects. Present work was designed to evaluate the effect of three week’s oral administration of aqueous extract of herbal tea, made from a Chinese herb Ginseng and Malva Verticillata (GMV) on overweight Albino Wistar rats. We found inverse relationship between body weight and serotonin level in whole brain and also found increased levels of tryptophan and serotonin metabolite 5-hydroxyindoleacetic Acid (5-HIAA) in both plasma and whole brain of test animals.