• Because Orlistat's main effect is to prevent dietary fat from being absorbed, the fat is excreted unchanged in the feces and so the stool may become oily or loose. Increased flatulence is also common.
  

• Frequent or urgent bowel movements
  

• rare occurrences of fecal incontinence

Side effects are most severe when beginning therapy, and decrease in frequency with time. (less than a week, but some may persist for over six months).


important!

Foods with high fat content should be avoided; the manufacturer advises consumers to follow a low-fat, reduced-calorie diet. Oily stools and flatulence can be controlled by reducing the dietary fat content to somewhere in the region of 15 grams per meal.

Absorption of fat-soluble vitamins and other fat-soluble nutrients is inhibited by the use of orlistat. A multivitamin tablet containing vitamins A, D, E, K, and beta-carotene should be taken once a day, at least 2 hours before or after taking the drug.


Some claims

A 2006 animal study addressed a connection orlistat shares with aberrant crypt foci (ACF), lesions found in the colon which are believed to be one of the earliest precursors of colon cancer.

Despite claims that orlistat increases the risk of breast cancer amongst clinical trial participants, there is evidence to suggest that the introduction of specific varied preparations containing orlistat, namely the concurrent administration of orlistat and the monoclonal antibody trastuzumab, can actually induce cell death in tumor cells and block their growth.

 
See full Orlistat alli and Xenical diet pill review here