Metamucil typically takes about 12 to 72 hours (1 to 3 days) to work after taking it. This bulk-forming fiber laxative absorbs water, making the stool larger and softer, which helps to relieve constipation. It is important to take it with plenty of water for it to be effective and to avoid possible side effects like dehydration or cramping. If Metamucil does not help within about a week, it is advised to consult a healthcare professional.
