A newly discovered bacterial duo may be the hidden cause of chronic constipation. These two microbes break down the protective layer of mucus in the colon, leaving the stool dry and hard. Traditional laxatives do not solve this problem. Patients with Parkinson's disease have higher levels of these bacteria and often suffer from constipation years before tremors appear. Blocking a bacterial mucus-destroying enzyme prevented constipation in mice. This finding suggests a new strategy for the treatment of chronic constipation.