This clinical trial is designed to study the effects of rifampicin on the glucose, lipid and hormone homeostasis in healthy volunteers. The main hypothesis is that rifampicin lowers fasting glucose and enhances insulin sensitivity. The study is a randomized, placebo-controlled, open-label cross-over trial. Twelve subjects will be given 600 mg of rifampicin a day for a week compared to a one-week placebo arm. There is at least a 4-week wash-out between the arms. The main outcome measures are the changes in the fasting glucose and HOMA-IR-index (calculated based on fasting glucose and insulin).