Background While it is generally acknowledged that self-prescribing among physicians poses some risk, research finds such behaviour to be common and in certain cases accepted by the medical community. Largely absent from the literature is knowledge about other activities doctors perform for their own medical care or for the informal treatment of family and friends. This study examined the variety, frequency and association of behaviours doctors report providing informally. Informal care included prescriptions, as well as any other type of personal (...) medical treatment (eg, monitoring chronic or serious conditions). Method A survey was sent to 2500 randomly-selected physicians in Colorado, 600 individuals returned questionnaires with usable data. The authors hypothesised: (1) physicians would prescribe the same types of treatment at home as they prescribed professionally; and (2) physicians who informally prescribed addictive medications would be more likely to engage in other types of informal medical care. Results Physicians who wrote prescriptions for antibiotics, psychotropics and opioids at work were more likely to prescribe these medications at home. Those prescribing addictive drugs outside of the office treated more serious illnesses in emergency situations, more chronic conditions and more major medical/surgical conditions informally than did those not routinely prescribing addictive medications. Physicians reported a variety of informal care behaviour and high frequency of informal care to family and friends. Discussion The frequency and variety of informal care reported in this study strongly argues for profession-wide discussion about ethical and guideline considerations for such behaviour. These areas are discussed in the paper. (shrink)