Are there any serious side effects of Orlistat?

The most common side effects of Orlistat (Orlistat) are flu, low blood sugar, headache, upper respiratory tract infection (cold), rectal greasy spots, abdominal (stomach) pain or discomfort, gas (bloating), and urgency to have a bowel movement (urgent need to have a bowel movement). (stools), fatty or oily stools, gas, liquid stools, oily (stool) and increased bowel movements usually first occur within 3 months of starting treatment. Approximately 50% of gastrointestinal adverse events associated with orlistat treatment last less than 1 week, and most last less than 4 weeks. The following adverse reactions have been found during the post-marketing use of orlistat, and reports of liver failure, acute oxalate nephropathy, pancreatitis, and lower gastrointestinal bleeding have been observed.