There are different types of laxatives: bulk-forming (fibre-based), osmotic (draw water into the bowel), stimulant (speed up the bowel) and stool softeners. For occasional constipation, a pharmacist can recommend a suitable one and explain how and how long to use it. Drink plenty of water, especially with bulk-forming types.
Long-term, frequent laxative use, particularly stimulant types, is best avoided unless a doctor advises, because the goal should be to fix the cause through diet, fluids, activity, and reviewing any constipating medicines.
See a doctor if you find you need laxatives most days, if constipation keeps returning, or if it comes with warning signs such as blood in the stool, unexplained weight loss, persistent pain, or a lasting change in bowel habit. In pregnancy or for children, get tailored advice before using laxatives.