CAR T cell therapy has significantly improved treatment outcomes for patients with relapsed or refractory B-cell acute lymphoblastic leukemia, large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, and multiple myeloma. However, it can cause various adverse effects requiring monitoring and management at specialized centers, contributing to morbidity and non-relapse mortality. These toxicities include cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS), and immune effector cell-associated hematotoxicity. This review discusses the pathophysiology and management of these toxicities. CRS is a supraphysiologic immune response following CAR T therapy, characterized by fever, hypotension, and organ dysfunction. It is graded using the ASTCT consensus criteria, with treatment involving tocilizumab and corticosteroids. Factors associated with CRS risk include higher CAR T dose, CD28 costimulatory domain, and disease burden. Management of CRS involves supportive care, corticosteroids, and anti-cytokine therapy. ICANS is a neurotoxicity associated with CAR T therapy, characterized by neurological symptoms such as tremor, seizures, and cognitive impairment. It is graded using the ASTCT consensus criteria, with treatment involving corticosteroids, anti-epileptic drugs, and IL-1 inhibitors like anakinra. Factors associated with ICANS risk include higher CAR T dose, CD28 costimulatory domain, and disease burden. Management of ICANS involves supportive care, corticosteroids, and anti-IL-1 therapy. The management of CRS and ICANS requires careful monitoring and intervention to prevent severe complications. Anti-cytokine therapy, corticosteroids, and targeted therapies like IL-1 inhibitors are used to manage these toxicities. Prophylactic approaches are being investigated to reduce the incidence and severity of these toxicities. The role of IL-1 and IL-6 in the pathophysiology of these toxicities is being explored, with IL-1 inhibitors showing promise in the treatment of refractory cases. Further research is needed to optimize the prevention and treatment of these toxicities to improve patient outcomes.CAR T cell therapy has significantly improved treatment outcomes for patients with relapsed or refractory B-cell acute lymphoblastic leukemia, large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, and multiple myeloma. However, it can cause various adverse effects requiring monitoring and management at specialized centers, contributing to morbidity and non-relapse mortality. These toxicities include cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS), and immune effector cell-associated hematotoxicity. This review discusses the pathophysiology and management of these toxicities. CRS is a supraphysiologic immune response following CAR T therapy, characterized by fever, hypotension, and organ dysfunction. It is graded using the ASTCT consensus criteria, with treatment involving tocilizumab and corticosteroids. Factors associated with CRS risk include higher CAR T dose, CD28 costimulatory domain, and disease burden. Management of CRS involves supportive care, corticosteroids, and anti-cytokine therapy. ICANS is a neurotoxicity associated with CAR T therapy, characterized by neurological symptoms such as tremor, seizures, and cognitive impairment. It is graded using the ASTCT consensus criteria, with treatment involving corticosteroids, anti-epileptic drugs, and IL-1 inhibitors like anakinra. Factors associated with ICANS risk include higher CAR T dose, CD28 costimulatory domain, and disease burden. Management of ICANS involves supportive care, corticosteroids, and anti-IL-1 therapy. The management of CRS and ICANS requires careful monitoring and intervention to prevent severe complications. Anti-cytokine therapy, corticosteroids, and targeted therapies like IL-1 inhibitors are used to manage these toxicities. Prophylactic approaches are being investigated to reduce the incidence and severity of these toxicities. The role of IL-1 and IL-6 in the pathophysiology of these toxicities is being explored, with IL-1 inhibitors showing promise in the treatment of refractory cases. Further research is needed to optimize the prevention and treatment of these toxicities to improve patient outcomes.