This is a common problem as we get older, since we do not eat so much, nor do we take as much exercise. Often drugs prescribed by the doctor (eg water tablets ; pain-killers) lead to constipation. It doesn't matter if you don't go to the toilet every day or even only once or twice a week. It is more important that the motions are not hard. By drinking plenty of fluids and eating fibre, eg brown bread, bran, vegetables and fruit, most people can manage alright. Do not take laxatives such as Senna on a regular basis.