This paper addresses blood management in injecting drug use through a thematic analysis of 59 qualitative interviews about HCV and HIV. Blood management is rarely considered in the drug policy literature, particularly from the perspective of people who inject drugs and in connection with social theory. The analysis draws on the risk governance literature, in particular the idea of altruistic conduct and utopian visions of perfect risk management. Interviewees made a distinction concerning seen and unseen bleeding in injection situations. Bleeding was either ordinary or exceptional, but in either case open to direct surveillance. Unseen blood in injecting settings was a new and anxiety-provoking idea, partly because it undermined blood management. A related concern of blood management is containing blood through competent drug injection. Cleanliness also figured in blood management in terms of cleaning the self and injection settings and injecting with clean people. Implications for harm reduction include the need to address awareness of the possible presence of unseen blood in injecting settings without undermining security or furthering a sense of fallibility on the part of injecting drug users in blood management practice. © 2004 Published by Elsevier B.V.