About a third of endometriosis patients using cannabis reported side effects, but some of those effects might actually be helpful

In an international survey of people with endometriosis using cannabis, 32% reported side effects, but the researchers argue some commonly labeled adverse effects (like appetite changes and sedation) may have therapeutic value for this population.

Sinclair, Justin et al.·The Australian & New Zealand journal of obstetrics & gynaecology·2026·Preliminary EvidenceCross-Sectional
RTHC-08628Cross SectionalPreliminary Evidence2026RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Cross-Sectional
Evidence
Preliminary Evidence
Sample
N=889

What This Study Found

Among endometriosis patients using cannabis for symptom management, 32% experienced side effects, consistent with published literature. However, the study suggests that some reported adverse effects may have clinical utility in the endometriosis population and require more nuanced interpretation.

Key Numbers

889 participants in the larger survey. 32% of cannabis users reported side effects. The study was a subset analysis examining whether reported adverse effects have therapeutic relevance.

How They Did This

Subset analysis of a larger international survey (n=889) investigating self-reported effectiveness, safety, and pharmaceutical de-prescribing trends of cannabis use among people with endometriosis.

Why This Research Matters

Endometriosis patients are increasingly turning to cannabis for pain management, often without medical guidance. Reframing certain "side effects" as potentially beneficial challenges the binary categorization of drug effects and could inform more patient-centered care.

The Bigger Picture

The concept that a side effect in one context can be therapeutic in another is well-established in medicine (sedation as a side effect vs. a sleep aid). This study applies that lens to cannabis use in endometriosis, where symptoms like poor appetite, insomnia, and anxiety often co-occur with pain.

What This Study Doesn't Tell Us

Survey-based self-reported data. Subset of a larger study, so the specific sample size for this analysis is unclear. No clinical verification of endometriosis diagnosis or cannabis use. International sample with varying legal and product quality contexts.

Questions This Raises

  • ?Which specific cannabis side effects do endometriosis patients find beneficial?
  • ?Does the therapeutic reframing of side effects change prescribing or counseling practices?
  • ?How do these patterns differ by cannabis product type?

Trust & Context

Key Stat:
32% reported side effects, some potentially therapeutically useful
Evidence Grade:
Preliminary: survey-based subset analysis with self-reported data and no clinical verification.
Study Age:
Published 2026.
Original Title:
Cannabis and Endometriosis: When Is an Adverse Effect Not Adverse?
Published In:
The Australian & New Zealand journal of obstetrics & gynaecology, 66(1), e70076 (2026)
Database ID:
RTHC-08628

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study

A snapshot of a population at one point in time.

What do these levels mean? →

Frequently Asked Questions

Do people with endometriosis experience side effects from cannabis?

About 32% reported side effects in this international survey, a rate consistent with the broader cannabis literature.

Can cannabis side effects be beneficial for endometriosis patients?

The researchers suggest that effects typically labeled as adverse, such as appetite changes and sedation, may actually address co-occurring endometriosis symptoms.

Read More on RethinkTHC

Cite This Study

RTHC-08628·https://rethinkthc.com/research/RTHC-08628

APA

Sinclair, Justin; Adler, Hannah; Eathorne, Allie; Holtzman, Orit; Ee, Carolyn; Abbott, Jason; Sarris, Jerome; Armour, Mike. (2026). Cannabis and Endometriosis: When Is an Adverse Effect Not Adverse?. The Australian & New Zealand journal of obstetrics & gynaecology, 66(1), e70076. https://doi.org/10.1111/ajo.70076

MLA

Sinclair, Justin, et al. "Cannabis and Endometriosis: When Is an Adverse Effect Not Adverse?." The Australian & New Zealand journal of obstetrics & gynaecology, 2026. https://doi.org/10.1111/ajo.70076

RethinkTHC

RethinkTHC Research Database. "Cannabis and Endometriosis: When Is an Adverse Effect Not Ad..." RTHC-08628. Retrieved from https://rethinkthc.com/research/sinclair-2026-cannabis-and-endometriosis-when

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.