Active lymphoma generally refers to aggressive lymphoma as opposed to inert lymphoma, and mainly includes diffuse large B lymphoma, among others. Lymphoma is a group of malignant tumors originating in the lymph nodes and lymphoid tissues. Active lymphoma refers to a group of non-Hodgkin’s lymphomas, also called aggressive lymphomas, as opposed to inert lymphomas. Aggressive lymphomas mainly include diffuse large B-cell lymphoma, Burkitt lymphoma/leukemia, angioimmunoblastic T-cell lymphoma, mesenchymal large cell lymphoma, and peripheral T-cell lymphoma (non-specific), which generally have rapid progression and poor prognosis. When patients present with painless progressively enlarged lymph nodes, they should consult a doctor promptly to avoid delay.