Alliorlistat
According to the FDA label: Use for weight loss in overweight adults, 18 years and older, when used along with a reduced-calorie and low-fat diet
23,376 adverse event reports submitted to the FDA (2004–2026)
Top Reported Adverse Events
The most frequently reported events in association with Alli in the FAERS database. These are events reported by patients taking this medication, not necessarily caused by it. A single report may include multiple events.
Show these terms with plain-language definitions
Tap any term below for a plain-language definition.
Drug Ineffective 4,350 reports
A report that the medication did not work as expected for the person taking it. This is a reporting category, not a sign the drug is defective. It simply means someone felt it was not helping their condition.
Full definition in the glossary →- Rectal Discharge 2,421 reports
Gastrointestinal Disorder 2,152 reports
A general report of a problem affecting the digestive system, used when no more specific condition is named.
Full definition in the glossary →Constipation 1,912 reports
Difficulty passing stool, or having fewer bowel movements than usual.
Full definition in the glossary → See all drugs reporting this event →Weight Increased 1,817 reports
Diarrhoea 1,811 reports
Loose or watery bowel movements, often frequent. Also spelled diarrhea in American English.
Full definition in the glossary → See all drugs reporting this event →Flatulence 1,585 reports
Excess gas in the digestive system, commonly called passing gas.
Full definition in the glossary →- Steatorrhoea 1,573 reports
Abdominal Pain Upper 1,285 reports
Pain in the upper part of the belly, above the navel.
Full definition in the glossary →Headache 1,016 reports
Pain in the head or upper neck.
Full definition in the glossary → See all drugs reporting this event →Abdominal Distension 971 reports
A swelling or bloating of the belly.
Full definition in the glossary → See all drugs reporting this event →Nausea 832 reports
The feeling of sickness in your stomach that often comes before vomiting.
Full definition in the glossary → See all drugs reporting this event →Treatment Noncompliance 800 reports
A report that a person did not take a treatment as prescribed. This is a reporting category describing what happened, not a judgment about the person.
Full definition in the glossary →Malaise 735 reports
A general feeling of being unwell or uncomfortable, without a specific symptom.
Full definition in the glossary →- Frequent Bowel Movements 625 reports
Ranked by frequency of reports, not severity. The most-reported event is not necessarily the most dangerous or the most common in patients taking this drug.
Who Is Reporting
Demographics of patients in FAERS reports that included this information. Not all reports include patient demographics.
By Sex
View reporter sex data as a table
| Sex | Reports |
|---|---|
| Female | 14,390 |
| Male | 1,896 |
| Unknown | 45 |
By Age Group
View age group data as a table
| Age group | Reports |
|---|---|
| 0-17 | 82 |
| 18-34 | 2,564 |
| 35-49 | 3,885 |
| 50-64 | 3,464 |
| 65-74 | 954 |
| 75+ | 279 |
This shows who filed reports, reflecting who takes this drug and who tends to report, not who is at greatest risk.
Reported Outcomes
Outcomes recorded in FAERS reports that included Alli. A single report may involve multiple reactions, each with a different outcome. These categories are defined by FDA reporting guidelines, not by PillSignal.
View outcome data as a table
| Outcome | Reports |
|---|---|
| Non-Serious | 18,776 |
| Other Serious | 3,278 |
| Hospitalization | 1,413 |
| Disability | 226 |
| Life-Threatening | 193 |
| Death | 115 |
Serious outcomes are far more likely to be reported than mild ones, so this overstates how often outcomes are serious. A recorded death does not mean the drug caused it.
Report Volume Over Time
Number of FAERS reports received per quarter for Alli. Changes in volume may reflect shifts in prescribing rates, media attention, or reporting behavior, not changes in the medication's safety profile.
View report trend as a table
| Year | Reports |
|---|---|
| 2004 | 29 |
| 2005 | 42 |
| 2006 | 31 |
| 2007 | 7,978 |
| 2008 | 5,952 |
| 2009 | 602 |
| 2010 | 493 |
| 2011 | 290 |
| 2012 | 177 |
| 2013 | 122 |
| 2014 | 1,177 |
| 2015 | 1,801 |
| 2016 | 669 |
| 2017 | 673 |
| 2018 | 660 |
| 2019 | 577 |
| 2020 | 497 |
| 2021 | 428 |
| 2022 | 201 |
| 2023 | 340 |
| 2024 | 315 |
| 2025 | 260 |
| 2026 (partial) | 62 |
The steep increase around 2004 reflects the FDA's move to electronic submission, not a change in this drug's safety. Trends track reporting volume, not risk.
Medications commonly reported with Alli
In FDA adverse event reports that mention Alli, these medications appeared most often in the same report.
- Metformin (332 reports)
- Aspirin (312 reports)
- Omeprazole (259 reports)
- Simvastatin (255 reports)
This reflects co-occurrence in submitted reports, not evidence of drug interaction or combined risk. People often report several medications taken for the same condition or for unrelated reasons. Talk to a doctor or pharmacist about your specific medications.
Related Drugs
Other medications with similar adverse event profiles in FDA FAERS reports.
Data Source
This data is sourced from the FDA's Adverse Event Monitoring System (AEMS), formerly FAERS, via the OpenFDA API. PillSignal is not affiliated with the FDA.
View this data on the FDA website →Data last updated: June 2026