The apparatus and method for detecting blood in urine or feces includes a photodetector configured to detect a transient light emitted in a toilet bowl by luminol and an oxidizer catalyzed by iron in the blood. The apparatus may include dispensers for the luminol, the oxidizer and a base. The apparatus may include a microprocessor and a network connection and may perform statistical analyzes, store data and alert the patient or a healthcare provider if blood is detected. The photodetector may be configured to detect light emitted in the toilet bowl by a fluorophore present in the water and excited by the transient light from the luminol and oxidizer.