Abstract: Iran has been one of the highest users of diphenoxylate in the world in 2008. Iranian food and drug organisation (FDO) established some rules to control the usage of this drug included rationalizing the supply and doubling the price. Data were gathered from the distributors and wholesalers of this medicine in the country during 2006-2010. These data were cross-checked with importation data in the Ministry of Health and a trend analysis was tabulated. In 2009, the average consumption reached to less than 650 million tablets which show 42% decrease in comparison to the previous year. After the second intervention, there has been no significant change in the trend. The first intervention has controlled the use of diphenoxylate by reduction of market need and lessening diphenoxylate unauthorized use. Data do not support the efficiency of second intervention meaning that doubling the price does not work.