The parasite is widely conceived as a negative figure that takes without giving; perceived as an agent of corruption and destruction, it is subjected to programmes of eradication and expulsion across cultural, economic, political and ethical contexts. This paper offers an alternative approach to the status of parasitic relations in light of Michel Serres’s The Parasite, elaborated through ethnographic research into the after-hours culture and hidden economy of London’s Borough Market. We highlight the mutual dependence of agents in host-parasite networks according to what we term ‘general parasitism’, while inquiring into its ethical potential. Ultimately, we argue that while taking into account the near ubiquity of parasitic relations cannot form the basis for any concrete axiomatic ethical paradigm, it should at least encourage an ethics of hesitation before judgement when faced with any apparent instance of parasitism: to presume that parasitism is undesirable and unethical is itself undesirable and unethical.