Over the last few years there has been increased societal pressure on the one hand and self-generated scientific pressure on the other to develop new and better in vitro techniques for the evaluation of the safety of commercial products. In vitro methodology addresses four major areas within toxicology. It provides the basic science of the discipline with new information. In acute toxicity testing, it can provide alternatives to current approaches, e.g. the Draize irritation tests. In the area of chronic toxicity testing, it will allow us to define the mechanisms associated with organ specific insults. In the area of risk assessment, the combined knowledge obtained by superior methods will allow us to assess risk more accurately. The results of studies on alternatives to the Draize irritation tests being carried out at or supported by The Johns Hopkins Center for Alternatives to Animal Testing will be reviewed.