Background Most people who are dying want to be cared for at home, but only half of them achieve this. The likelihood of a home death often depends on the availability of able and willing lay carers. When people who are dying are unable to take oral medication, injectable medication is used. When top-up medication is required, a health-care professional travels to the dying person’s home, which may delay symptom relief. The administration of subcutaneous medication by lay carers, although not widespread UK practice, has proven to be key in achieving better symptom control for those dying at home in other countries. Objectives To determine if carer administration of as-needed subcutaneous medication for common breakthrough symptoms in people dying at home is feasible and acceptable in the UK, and if it would be feasible to test this intervention in a future definitive randomised controlled trial. Design We conducted a two-arm, parallel-group, individually randomised, open pilot trial of the intervention versus usual care, with a 1 : 1 allocation ratio, using convergent mixed methods. Setting Home-based care without 24/7 paid care provision, in three UK sites. Participants Participants were dyads of adult patients and carers: patients in the last weeks of their life who wished to die at home and lay carers who were willing to be trained to give subcutaneous medication. Strict risk assessment criteria needed to be met before approach, including known history of substance abuse or carer ability to be trained to competency. Intervention Intervention-group carers received training by local nurses using a manualised training package. Main outcome measures Quantitative data were collected at baseline and 6–8 weeks post bereavement and via carer diaries. Interviews with carers and health-care professionals explored attitudes to, experiences of and preferences for giving subcutaneous medication and experience of trial processes. The main outcomes of interest were feasibility, acceptability, recruitment rates, attrition and selection of the most appropriate outcome measures. Results In total, 40 out of 101 eligible dyads were recruited (39.6%), which met the feasibility criterion of recruiting > 30% of eligible dyads. The expected recruitment target (≈50 dyads) was not reached, as fewer than expected participants were identified. Although the overall retention rate was 55% (22/40), this was substantially unbalanced [30% (6/20) usual care and 80% (16/20) intervention]. The feasibility criterion of > 40% retention was, therefore, considered not met. A total of 12 carers (intervention, n = 10; usual care, n = 2) and 20 health-care professionals were interviewed. The intervention was considered acceptable, feasible and safe in the small study population. The context of the feasibility study was not ideal, as district nurses were seriously overstretched and unfamiliar with research methods. A disparity in readiness to consider the intervention was demonstrated between carers and health-care professionals. Findings showed that there were methodological and ethics issues pertaining to researching last days of life care. Conclusion The success of a future definitive trial is uncertain because of equivocal results in the progression criteria, particularly poor recruitment overall and a low retention rate in the usual-care group. Future work regarding the intervention should include understanding the context of UK areas where this has been adopted, ascertaining wider public views and exploring health-care professional views on burden and risk in the NHS context. There should be consideration of the need for national policy and of the most appropriate quantitative outcome measures to use. This will help to ascertain if there are unanswered questions to be studied in a trial.