A before-after study was performed without a control group. A multidisciplinary team was created in Catalonia, Spain, to intervene in nursing homes. This team combined general practitioners, nurses, social and administrative workers from primary care, clinicians and nurses assigned to the nursing homes, and a clinical pharmacologist. The intervention consisted of developing an improvement plan, reviewing the validity of prescriptions and medication plans in this population. The study population were all patients admitted to the 5 nursing homes intervened belonging to the North area of Barcelona. Patients were followed up from the intervention that began in June 2020 until approximately one year later or until death if prior. The inclusion criteria was institutionalized patients with public health coverage provided by CatSalut. The exclusion criteria were institutionalized patients with health coverage provided by other insurers, a short-term life expectancy, hospitalized during the intervention, who died or were discharged in the first month of review and who could not be reviewed due to lack of information. There was no formal sample size calculation since the analysis was done on all the reviewed patients, except those excluded. First, a detailed description of the clinical characteristics, chronic diseases and pharmacological treatments will be made. Also a descriptive analysis of incomplete data, interactions, duplications, contraindications and drugs deemed inappropriate or of doubtful efficacy. Secondly, a descriptive analysis of the number of drugs prescribed, withdrawn, added, and that were recommended to be withdrawn, changed or adequated will be made. Also a comparative analysis of changes in the number of drugs, use of absorbents and if recommendations were followed.