Dietary supplements are preparations manufactured from concentrated sources of nutrients or other substances with nutritional or physiological effect with purpose to enrich usual diet and to maintain health as aim. They are regulated by food laws and regulations, but because they often contain the same active ingredients as drugs this raises the question whether they should be regulated as food or medicine. In accordance with good manufacturing practices, which pharmaceutical companies apply, almost every aspect of the production cycle is recorded which opens the possibility for the application of that methodology that can improve processes by the processing existing data. The success or the ability of the process can be determined by statistical analysis of existing data for a particular product and thus can estimate the possibility for its improvement. Statistical control shows the variability of results within the range of specification requirements and processes spread within the range of ± 3 standard deviations (6σ) in relation to the mean value of the processed results. Based on the above, the process capability index that represents the ratio of the given range for the parameter in relation to the actual dispersion of results can be calculated. By such monitoring a good foundation for the implementation of the "six sigma" methodology, which is designed to reduce process variation, increase the level of product quality and also increase the profitability of the product can be achieved. "Six Sigma" means a possibility that during production will be a maximum of 3.4 defects per million events. This paper presents statistical control of 15 batches of dietary supplement, produced in a period of three years. The processed data include the results of utilization in different stages of production and packaging, the results of process parameters (such as mass, thickness, hardness and disintegration of tablet cores and film-tablets) and the results of quality control of finished product (such as content of active substance, content of heavy metals and disintegration of film-tablets). Based on these results, effectiveness of the process and the quality of the tested product are estimated.