In order to assess the significance of drug levels measured in clinical and forensic toxicology as well as for Therapeutic Drug Monitoring (TDM) it is essential that good collections of data are readily available. For more than 800 substances, therapeutic ('normal') and, if data was available, toxic, and fatal plasma concentrations as well as elimination half-lives were compiled in a table. The compilation includes data for hypnotics, benzodiazepines, neuroleptics, antidepressants, sedatives, analgesics, anti-inflammatory agents (e.g., NSAIDs), antihistamines, antiepileptics, betaadrenergic antagonists, antibiotics (penicillins, cephalosporins, aminoglycosides, gyrase inhibitors), diuretics, calcium-channel blockers, cardiac glycosides, antiarrhythmics, antiasthmatics, ACE-inhibitors, opiate agonists, and local anesthetics, among others. In addition, toxicologically relevant xenobiotics were listed. Data have been abstracted from published information, both compilations and primary sources and have been completed with data collected in our own forensic and clinical toxicology laboratories. Wherever possible, ranges for therapeutic plasma concentrations are expressed as trough concentration at steady state. The half-life values given for each drug are chosen to represent the terminal log-linear phase at most. It is the purpose to rapidly assess the significance of drug levels for the therapeutic monitoring of patients, and to facilitate the diagnostic and clinical assessment in case of intoxications.