Medical research ethics, with its focus on preventing participants from being exploited or exposed to undue risk, has almost entirely neglected researchers' ancillary-care obligations-their obligations to provide participants with medical care that they need but that is not required in order to carry out the researchers' scientific plans safely. To begin to develop a theoretical account of researchers' ancillary-care obligations, this paper develops and explores the more general idea of moral entanglements. Of interest in its own right, this category comprises the ways in which, through innocent transactions with others, we can unintendedly accrue special obligations to them. More particularly, the paper explains intimacy-based more entanglements, to which we become liable by accepting another's waiver of privacy rights. Sometimes, having entered into other's private affairs for innocent or even helpful reasons, one discovers needs of theirs that then become the focus of special duties of care. The general duty to warn them of their need cannot directly account for the full extent of these duties, but does indicate why a silent retreat is impermissible. The special duties of care importantly rest on a transfer of responsibilities that accompanies the privacy waivers. The result is a special obligation of beneficence that, like researchers' ancillary-care obligations, is grounded in a voluntary transaction despite not having been voluntarily undertaken.