Abstract
Background
We aimed to elucidate the effects of rectal douching on gut microbial communities and their associated metabolites in men who have sex with men (MSM).
Methods
A community sample of HIV-uninfected MSM were recruited in Guangzhou, China. Participants were stratified into rectal douching and non-douching groups based on their rectal douching behavior within the past three months. Peripheral blood and fecal samples were collected. Serum markers of microbial translocation were quantified using enzyme-linked immunosorbent assay (ELISA). Gut microbiota composition was assessed via 16S rRNA gene sequencing of fecal samples, and microbial metabolites were profiled using a mass spectrometry-based platform.
Results
This study enrolls a total of 51 HIV-uninfected MSM (20 in the rectal douching group and 31 in the non-douching group). The two groups have comparable age distributions [median age: 25 years, interquartile range (IQR): 23-30 vs. 27 years, IQR: 24-31]. Significant structural shifts in microbial community composition are observed at both the phylum and genus levels in the rectal douching group relative to the non-douching group. The relative abundances of the genera Clostridium, Lachnospira, and Turicibacter are significantly lower in the rectal douching group compared to the non-douching group. Furthermore, rectal douching significantly alters a wide range of microbial metabolites. Notably, rectal douching appears to reduce gut barrier integrity, as evidenced by significantly elevated levels of the microbial translocation marker lipopolysaccharide-binding protein (LBP) in the rectal douching group.
Conclusions
Rectal douching among HIV-uninfected MSM is associated with gut microbiota dysbiosis, significant alterations in microbial metabolic profiles, and reduced gut barrier integrity. These findings underscore the need for increased awareness and health education within this population.
Plain language summary
Some men who have sex with men (MSM) clean their rectum before sex for hygiene, a practice known as rectal douching. While it is common, its effects on gut health are not well understood. We studied two groups of MSM: those who douche and those who do not, comparing their gut bacteria, related metabolites, and gut barrier markers. Our findings show that douching disrupts the balance of gut bacteria, reduces levels of beneficial bacterial products, and may weaken the gut’s protective barrier, potentially increasing infection risk. This reveals a new way that douching can harm gut health, beyond simple physical irritation. Our research underscores the importance of clear health communication about these risks and the need for safer hygiene practices.
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Data availability
The datasets generated and/or analyzed during the current study are provided as Supplementary Data files.
Code availability
All custom code used for data preprocessing is not publicly available, but is available from the corresponding author on reasonable request.
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Acknowledgements
The authors thank Yonghong Li and Lijuan Chen from Guangzhou Eighth People’s Hospital for their assistance in data collection. We thank Hao Wu and Yanshan Cai from the Guangzhou Center for Disease Control and Prevention for their technical assistance with sample processing and preservation. We thank all participants, participating organizations and individuals who contributed to this study. This study was supported by the National Key Technologies R&D Program (2023YFC2306700), the Prevention and Control of Emerging and Major Infectious Diseases-National Science and Technology Major Project (2025ZD01905200), the National Natural Science Foundation of China (82574167), and the Fujian Province High-Level Talent Recruitment Program (TD202307). All funding parties did not have any role in the design of the study or in the explanation of the data.
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This study was conceived and designed by Huachun Zou and Linghua Li. Heping Zhao, Anping Feng and Dan Luo were responsible for data compilation and data analysis. All authors have contributed to the interpretation of data and study findings. Heping Zhao and Fenqi Da drafted the paper with all authors critically reviewing the paper.
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Zhao, H., Feng, A., Luo, D. et al. Rectal douching is associated with gut dysbiosis and metabolic disruption in HIV-uninfected men who have sex with men. Commun Med (2026). https://doi.org/10.1038/s43856-026-01490-0
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DOI: https://doi.org/10.1038/s43856-026-01490-0
