The goal of this study was to observe the therapeutic efficacy of cyclophosphamide, vincristine and prednisone combined chemotherapy (COP) in treating adult haemophagocytic lymphohistiocytosis (HLH). Fifteen cases diagnosed with HLH were enrolled in our study. Each of them was treated with the COP regimen. Two of the fifteen patients had autoimmune disease-associated HLH (13.3%), 2/15 had lymphoma-associated HLH (13.3%), 7/15 had infection-associated HLH (IAHLH) (46.7%), and the remaining 4/15 developed the disease in the absence of apparent underlying disease (26.7%). A complete response (CR) was achieved in 7/15 patients (46.7%), while a partial response (PR) was achieved in 5/15 patients (33.3%). With a mean follow-up of 72.5 weeks, the one-year overall survival was 66.7%. HLH of varying aetiology exhibited differing sensitivity and response to the COP regimen. In combination with aetiological and supportive treatment, the COP regimen as a mild and cost-effective chemotherapy is especially favourable for IAHLH, autoimmune disease-associated HLH, and disease severity precluding intensive treatment.