Treatment with a mixture of Cyperus rotundus, Iris versicolor and Holoptelia integrifolia resulted in a rapid decrease of weight in and ad libitum fed obese rats. Body fat and Fat: Protein ratio were much less while food consumption, body protein, energy expenditure and metabolic rate were more in mixture treated obese rats than in food restricted obese. A mixture of these plant preparations, therefore, possesses the property to reduce obesity by increasing energy expenditure and metabolic rate in obese rats.