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Alli: Everything You Need to Know

Side Effects of Alli

Loose stools and other bowel movement changes are the most common side effects of Alli. Symptoms typically occur during the first few weeks of treatment and then go away. However, they may continue.

Tell your doctor if you have any of the following symptoms and they become severe or do not go away:

  • Difficulty controlling bowel movements
  • Loose, frequent stools
  • Oily or fatty stools
  • Oily spots on undergarments
  • Stomach or rectum pain
  • Passing gas more often
  • Urgent need to have a bowel movement
  • Anxiety
  • Changes in your menstrual cycle
  • Headaches

Emergency Side Effects of Alli

Call your doctor or 911 immediately if you develop any of these symptoms:

  • Difficulty breathing
  • Difficulty swallowing
  • Hives or itching
  • Stomach pain that is severe or does not go away

Alli has been linked to severe liver injury in rare cases, though it has mostly occurred in those taking the prescription-strength dose (Xenical). Stop taking Alli and call your doctor immediately if you develop any of these possible signs of liver damage:

  • Dark urine
  • Fatigue
  • Fever
  • Light-colored stools
  • Loss of appetite
  • Severe, persistent itching
  • Weakness
  • Vomiting
  • Yellowing of the skin or eyes (jaundice)

WebMD Medical Reference

Reviewed by Kimball Johnson, MD on October 13, 2012

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