How Senna Works

• Senna is also available in tea form.tea image by Horticulture from Fotolia.com
  
  Within six to 12 hours after ingestion, senna reaches the colon. There, it interacts with enzymes to stimulate the bowel's nerves, causing the normal wave-like contractions of the digestive system to increase, ultimately producing a bowel movement.
  
  

Substitutes

• Prunes can work as well as other laxatives.pruneaux image by MONIQUE POUZET from Fotolia.com
  
  Senokot is available in tablet and liquid form. Substitutes include other sources of senna, such as powders and teas found at health food stores.
  
  People wishing to avoid taking senna have other laxative choices. These include stool softener--which increases the amount of fluid in the stool, making it easier to pass--and bulking agents such as psyllium. The old standby, prune juice, is also effective due to the large amounts of indigestible sorbitol contained in prunes.
  
  

Preventing Constipation

• High-fiber foods include most fruits and vegetables.vegetables image by dinostock from Fotolia.com
  
  The need for laxatives can often be prevented with a healthy lifestyle. Eat plenty of fiber-rich fruits, vegetables and whole grains. Exercise regularly, drink eight glasses of water daily, and don't resist the urge to have a bowel movement when the feeling strikes.