The working group of the Polish Society of Palliative Medicine has worked out the definition of constipation (as an agreed experts’ opinion), according to which constipation means decreased frequency of bowel movements to less than 3 per week or subjective patient’s complaints, such as difficulty in defecation, hard stools, straining or incomplete bowel movements. This study was aimed to verify the definition, especially with reference to frequency of bowel movements and practical implications of secondary prophylaxis of constipation. In the study bowel function questionnaire was applied in 265 patients. It has been proved the strong negative correlation between frequency of bowel movements and assessment of difficulty in defecation (Spearman’s rank correlation coefficient –0.67; p < 0.05), as well as significant worsening of subjective symptoms if number of days with defecation was less than 3 per week or if the time from the last bowel movements overcame 2 days. It is suggested to consider intensifying constipation prophylaxis if frequency of bowel movements is 3 per week and to avoid bowel movements less frequent than every second day.