Mammalian cell cultures have been around for decades—but they definitely aren’t going anywhere. They are increasingly valuable in drug development, for which the pharma industry is turning to cell-based assays for drug-safety testing because animal models are sometimes unreliable, or even inhumane. “For example, benzene will cause leukemia in people, but it doesn’t cause leukemia in mice,” says Don Finley, market segment manager for research cell culture at Sigma-Aldrich. “Because you can’t test experimental drugs in their early phases directly on humans, and animals alone aren’t perfect models, people turn to human cell-based assays as a way of determining whether a drug candidate is toxic, for example.” Cell-culture tools and expertise abound today, and it has never been a better time to learn the tricks of the trade. Perhaps you’ve helped with maintaining cultures, but now you’d like to start your own. Here are some main considerations to keep in mind when setting up your own cultures.