Which of the following is a contraindication for a cathartic?

A contraindication for using a cathartic is bleeding. When a patient is experiencing bleeding, especially in the gastrointestinal tract, the use of cathartics can exacerbate the situation. Cathartics increase bowel motility and can cause more aggressive contractions and pressure within the intestines, potentially leading to further injury or bleeding. Additionally, the presence of bleeding indicates a potential underlying pathology, and introducing a cathartic could complicate the clinical picture or delay necessary interventions.

In clinical practice, cathartics are primarily used to relieve constipation and clear the bowel prior to procedures, but they are not appropriate in cases where bleeding is present, as the risks they pose can outweigh the benefits.