During his routine TDM training he developed great interest into infectious diseases in critically ill patients. His research is focussed on the pharmacokinetics and pharmacodynamics of antimicrobial agents, in particular antifungal agents and anti-TB drugs. The aim is to optimize antimicrobial therapy based on PK/PD principles. The overall aim is to find a balance between efficacy and toxicity. Helpful tools are therapeutic drug monitoring, pharmacokinetic modeling, optimal sampling strategies. Also his more analytical oriented reasearch is focused on optimization of treatment by using alternative sampling strategies like dri ed blood spot sampling and oral fluid as alternative for plasma and serum.