Ex-Lax contains sennosides, a plant-based compound derived from the senna leaf that stimulates contractions in the bowel to relieve constipation. The regular strength version contains 15 mg of sennosides per tablet, while the maximum strength version contains 25 mg. Beyond the active ingredient, the specific inactive ingredients vary depending on whether you’re taking the pill form or the chocolate form.
The Active Ingredient: Sennosides
Sennosides are the only active ingredient in Ex-Lax. They belong to a class called stimulant laxatives, which work by triggering the muscles lining your intestines to contract and push stool through. This is different from fiber-based laxatives that bulk up stool or osmotic laxatives that draw water into the bowel. Stimulant laxatives are more aggressive, and they produce a bowel movement within 6 to 12 hours of taking a dose.
Sennosides come from the senna plant, which has been used as a laxative for centuries. When the compound reaches your large intestine, bacteria there convert it into its active form, which irritates the intestinal lining just enough to trigger those wave-like muscle contractions. It also reduces the amount of water your intestines reabsorb, keeping stool softer and easier to pass.
What’s in the Chocolate Version
Ex-Lax is probably best known for its chocolated form, which looks and tastes like a small piece of chocolate. The inactive ingredients in this version are cocoa powder, hydrogenated vegetable oils (palm kernel and palm), salt, soy lecithin, sugar, vanilla, and whey powder. If you have a dairy or soy allergy, this version contains both. The active ingredient is the same sennosides found in the tablet form.
Dosing by Age and Strength
For the regular strength product, adults and children 12 and older can take 2 tablets once or twice daily. Children ages 6 to under 12 can take 1 tablet once or twice daily. Children under 6 should not take Ex-Lax without a doctor’s guidance. The tablets should be swallowed whole with a glass of water, not crushed, broken, or chewed.
The maximum strength version doubles the sennosides per tablet to 25 mg, so the number of tablets per dose is lower. Regardless of which version you use, the label instructions are the ceiling, not a target. Start with the lowest effective dose.
Common Side Effects
Because sennosides work by stimulating your intestines, cramping is the most common side effect. You may also experience nausea, general stomach discomfort, or faintness. One harmless but sometimes alarming effect is brown or dark discoloration of your urine, which is a normal byproduct of how your body processes senna.
Rectal bleeding is the one side effect that signals something more serious. If that happens, stop taking Ex-Lax and contact a doctor.
Risks of Using It Too Often
Ex-Lax is designed for occasional use, not as a daily solution. Taking stimulant laxatives too frequently can lead to dependence, where your bowel stops functioning normally without the drug. Harvard Health Publishing describes this as the bowel essentially losing its ability to contract on its own after being chemically prompted too many times. This creates a cycle where you feel you need the laxative to have a bowel movement at all.
Long-term overuse can also disrupt your body’s electrolyte balance, particularly potassium and sodium levels, because the laxative prevents your intestines from reabsorbing water and minerals normally. Low potassium in particular can cause muscle weakness, irregular heartbeat, and fatigue. If constipation is a recurring problem for you rather than an occasional one, a different type of laxative or a dietary change is a better long-term approach than repeated use of a stimulant like Ex-Lax.