“…However, after studying adverse morphine effects in 122 Brazilian cancer children 7 , authors have observed that 72.9% of cases had constipation. Although being a relatively common manifestation in patients under opioids, it is worsened by several other factors such as malnutrition, dehydration and simultaneous use of other drugs, which are especially present in metastatic oncologic patients under palliative care 8 . Constipation is a challenge for the oncologic practice because it is often neglected by health professionals and caregivers, although being associated to several other symptoms, such as discomfort, abdominal pain, nausea, vomiting, fecal impaction with or without anal injury 4,5 , which invariably impact global health and quality of life of cancer patients, in addition to increasing the use of other drugs for relief or symptomatic treatment of symptoms and the rate of complications and costs related to such interventions.…”