The bottom line is that it is unlikely the senna was responsible, and on top of that, I am not advocating anything close to the amount of senna consumed when drinking multiple cups of dieter's tea. In the colon corrective we're now talking about, senna, along with the aloe and cascara sagrada, are merely colon cleansing stimulants for proper colon function. No one has ever suffered a problem from them when used in that regard.

The other claim sometimes made about herbal laxatives is that you become dependent on them to have a bowel movement. The evidence does not bear that out. Millions of people who did not have regular bowel movements before using colon cleansing products, have gone on natural colon cleansers, stayed on them for a number of months to build up colon function, and then weaned themselves off. The net result is that their colons are stronger and working better than before they started on the colon cleansing program. The trick is to wean yourself off, not stop abruptly. Just think how sensitive your colon is. Sometimes just taking a trip is enough to make you constipated. Your colon doesn't like abrupt changes.
To summarize: digestive disorders (including disorders of the gastrointestinal tract, as well as the liver, gallbladder, and pancreas) were responsible for over 50 million physician visits back in 1985--and more hospitalizations than any other category of medical problem in the United States 5, 6 and almost double that today. The total cost to the American public for all aspects of digestive disease is well over $100 billion per year.7 The most prevalent digestive diseases include:
In the colon, water is squeezed out and absorbed from food remnants, leaving behind a mixture of non-digestible fibre, bacteria, bile acids and cells that have been scraped off the intestinal wall. If bowel transit time is too slow, bacteria and fungi proliferate and toxins are reabsorbed. A healthy colon eliminates waste within six to 18 hours after every meal this means having two or three bowel movements a day. Clinical effects of colonic cleansing for general health promotion: a systematic review