Background: Flat tummy water (FTW) is an herbal tonic preparation made from cucumber (Cucumis sativus), lemon (Citrus limon), ginger (Zingerber officinale) and mint leaf (Mentha piperita) and is believed to be effective in the reduction of central/abdominal fat. While the potency and efficacy of FTW are hardly known, the present study presents a scientific investigation of its effect on high-fat-induced obese Wistar rat models.
 Methods: FTW was constituted using measured quantities of cut and infused cucumber, lemon and mint leaf while the individual plants were extracted and mixed to obtain an extract mixture (EM). Twenty-five (25) female Wistar rats were used for the study. They were divided into five (5) groups of five (5) animals each. Groups 1 & 2 served as the normal and negative controls and received standard rat chow/distilled water and high-fat diet/distilled water respectively. Groups 3, 4 & 5 served as the experimental groups. Group 3 received FTW ad libitum while groups 4 & 5 received 25 and 50mg/kg of extract mixtures (EM) respectively alongside the formulated high-fat diet. Lipid profile and serum glucose were determined using standard colourimetric methods. The body weight, naso-anal length, abdominal and thoracic circumferences (AC/TC) of the animals were measured before and after the experiment. 
 Results: There was a significantly reduced total cholesterol, triglycerides, low-density lipoproteins, very low-density lipoproteins and serum glucose and significantly increased high-density proteins among the obese animals treated with FTW and EM compared to the untreated obese negative control (p<0.05). The study also observed reduced body weight, AC/TC ratio and lee obesity index among treated obese animals when compared with the untreated negative control (p<0.05).
 Conclusion: The present study shows that the oral administration of flat tummy water (FTW) as well as extracts mixtures (EM) led to a moderate decrease in central abdominal obesity. FTW and EM showed potent anti-hyperlipidaemic, anti-hyperglycaemic and anti-obesity activity. This study concludes that these observed effects could be due to the synergistic action of cucumber (Cucumis sativus), lemon (Citrus limon), ginger (Zingerber officinale) and mint leaf (Mentha piperita).