In medicine, too, there is no free lunch – effective therapies come with side effects. But two new studies could make lunch cheaper for patients treated with chimeric antigen receptor (CAR) T cells. Researchers at the San Raffaele Hospital in Milan, Italy, and the Memorial Sloan Kettering Cancer Center (MSKCC) have gained new insights into the causes of cytokine release syndrome (CRS) and neurotoxicity, the two most serious forms of toxicity that are associated with CAR T cells.