This thesis investigates the supply chain of Vancomycin and Piperacillin/Tazobactam in order to understand why the two antibiotics have been exposed to back orders during recent years in Sweden. The health economical consequences due to these back orders of the two antibiotics was also examined. The used methods were literature search and elementary calculation methods. The supply chains for the two antibiotics consists of multiple manufacturing actors, both primary and secondary. The manufacturing actors are mostly located in low and middle income countries, which increases risks for the supply chains. The Swedish market is unattractive due to its small size and ineffective purchasing system, which also increases risks of shortages. The unattractive market is a probable cause of the lower amount of market authorisation holders which sell the antibiotics in Sweden. Furthermore, a financial model was created to assess the health economic impacts of shortages. The costs were calculated as the sum of the additional labor required to deal with shortages along with the costs of the alternative medicines. It was estimated that a shortage of Vancomycin can cost up to SEK 1 600 000 in fixed costs followed by up to SEK 202 997 per additional day of shortage and that a shortage of Pipetazo can cost up to SEK 1 600 000 in fixed costs followed by up to SEK 923 650 per day. There are also other negative aspects of these consequences, such as worsening of patient health and contributions to increased AMR.