Context: During a period of 6 months, 36 people reported to health authorities in the Department of Antioquia, Colombia, presenting episodes of bleeding in varying magnitude and locations in the body and alterations in coagulation tests, after having taken a falsified dietary supplement. The identification of the first four cases were to the cell-phone line at the Drug and Poison Research Information Center (CIEMTO). The successive presentation of cases with similar manifestations, taking the same product, served to suspect a possible common link.Case details: All of the patients needed hospitalization, the administration of blood products and / or vitamin K to reverse the clinical manifestations, and to stop the oral consumption of the falsified supplement. For each patient there was a full recovery of coagulation and improvement of haemorrhagic manifestations after the first week of management. The Food and Drug administration of Colombia (INVIMA), withdrew the product from the market, alerted the medical community and the general public and conducted an investigation that finally showed warfarin as a the main contaminant in the dietary supplement.Conclusion: This cases series emphasize the importance of the Poison Control Center to detect promptly potential new exposure of hazards to hundreds of products to the population, some of them fraudulent.