Ex-Lax Senna Chocolate Ex-Lax Senna Chocolate is used for the relief of occasional constipation. Ex-Lax Senna Chocolate is a scored chocolate bar of tablets which contain extract of senna which works gently overnight to help your body return to regularity. Ingredients The active ingredients are Sennosides (15mg). The other ingredients are Cocoa Liquor, Sucrose, Cocoa Butter, Lecithin and Vanilin. Directions Adults & elderly: 1 tablet at bedtime. Children 6-12 years: half a tablet. Under 6 years: not recommended.