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Senna

Brand names: Senokot, Ex-Lax

Senna is a plant-based stimulant laxative that relieves constipation, usually overnight.

Brand namesSenokot, Ex-Lax
Type of medicineStimulant laxative
Prescription?Over the counter
ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.

Overview

It's often taken with a stool softener, especially with opioid pain medicines.

What it's used for

  • Occasional constipation
  • Constipation from opioid pain medicines
  • Bowel prep (as directed)

How to take it

  • Take it at bedtime; it usually works in 6 to 12 hours.
  • Follow the label; don't use it longer than 1 week unless a provider says to.
  • For children, use only as directed by a provider.

Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.

Side effects

Common side effects

  • Belly cramps
  • Diarrhea
  • Brown or reddish urine (harmless)
Call your provider todayBleeding from the rectum
Call your provider todaySevere belly pain, or vomiting
Call your provider todayDiarrhea with weakness or dizziness

Warnings

  • Don't use it with belly pain, nausea, or vomiting unless a provider says to.

Other medicines, foods, and alcohol

  • Water pills add to potassium loss with heavy use.

Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.

Pregnancy and breastfeeding

Ask your provider.

Missed doses, overdose, and storage

If you miss a dose

This medicine is often taken only when needed. If you take it on a schedule, take a missed dose when you remember, unless it's almost time for the next one. Don't double up.

If someone takes too much

Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.

Storing it

Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.

Conditions it's used for

Sources

Last updated 2026-11-13.