This study aims to propose the use of Stochastic Model for a Period in order to promote the final products of a cosmetics company that, in a short time, would become obsolete considering a continuous demand and a standard normal distribution. The study of the outflow of outdated products in the market allows, through the application of different methodologies, to define values of promotional discount and / or decisions of destruction. This way it is possible to find the best solutions to avoid accumulation of obsolete stock and to ensure that the customers are satisfy with launches and renovations of products. By doing so the company s profitability, the image of their brand and the quality of their services provided is guaranteed. This paper will explain the methodology which is based on setting the discount values (S) that should be given to the old products, so that the total costs are minimized and the total profit maximized. The probabilistic model of inventory used was the one proposed by HOPP and SPEARMAN (2000). To obtain the promotional values it was necessary to estimate certain parameters such as the average and the variance of the demand based on the seasonality of sales in the last three years.