15. Asher Yatzar
4:5 A person should be careful to clean himself thoroughly after using the rest room since he would not be permitted to say anything holy, such as blessings, if he has even a small amount of excrement on him. The practice is to clean oneself using the weaker hand; this is because a man uses the stronger hand to put on his tefillin.
4:6 Whenever one uses the bathroom, he should wash his hands with water and say the blessing “asher yatzar,” that God created and sustains our miraculous bodies. The Mishnah Brurah clarifies that a person would recite asher yatzar even if a long time has passed since using the facilities, until he feels the need to go again (7:1). If a person forgot to recite asher yatzar and later uses the bathroom again, he only recites the blessing once. If a person takes a laxative and expects to go to the bathroom several times in a relatively short time span, he does not recite asher yatzar until he’s pretty sure he’s finished. The Mishnah Brurah (7:2) disagrees with this last point. In his view, a person would recite asher yatzar each time. The exception to this is if a person is having intestinal distress that is causing him to run constantly to the bathroom. In that case, he would have to wait until he thinks he’s finished.