Lipitor is a medication used to lower cholesterol levels in the blood. According to Drug Patent Watch [1], Lipitor's active ingredient is atorvastatin, which works by blocking an enzyme that the liver uses to produce cholesterol. However, like all medications, Lipitor can have side effects. One of the most common side effects of Lipitor is digestive issues, which may include nausea, diarrhea, and constipation [2]. These side effects are usually mild and go away on their own within a few days or weeks. In rare cases, Lipitor may cause more serious digestive problems, such as liver damage or pancreatitis [3]. It is important to talk to a doctor if you experience any unusual or severe symptoms while taking Lipitor.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4305860/