Khat chewing has an adverse effect on periodontal tissues


The Khat plant (Catha edulis) is native to the horn of Africa and the chewing of khat has been practiced for thousands of years.  It has a stimulant effect similar to amphetamine and an estimated 20 million regular users in Yemen and Eastern African countries.  It is classified as a drug of abuse by the World Health Organisation (WHO). Some studies have suggested that periodontal disease is more common if khat chewers while others have reported a benefit owing to anti plaque and anti-gingivitis features of the khat leaves.

The main aim of this review was to assess the effects of khat chewing on periodontal tissues.


Searches were conducted in the PubMed, Ovid Medline, Cochrane CENTRAL databases and grey literature sources including thesis at Sana’a University, Yemen and Cairo University, Egypt. Prospective randomised controlled clinical trials, controlled clinical studies (prospective or retrospective), and case-control studies investigating the impact of the khat chewing habit on periodontal tissues were considered.  respect of periodontal pocket depth, gingival recession and loss of attachment.

Two reviewers independently selected studies and abstracted data. Study bias was assessed using the domains Random selection of population, defined inclusion/exclusion criteria, loss of follow-up, validated measurement and statistical analysis. Studies with two or more domains absent were considered to be high risk. Meta-analysis was conducted if there were studies of similar comparisons reporting the same outcome measures.


  • 12 studies were included
  • 4 studies were considered to be a low risk of bias, 8 at moderate risk
  • A significant difference in favour of non-khat chewers was seen in both dichotomous
    • Pocket depth (3 studies; 2733 patients, 2039 chewers, 696 non-chewers) Odds ratio = 4.797(95%CI; 1.716-13.410)
    • Gingival recession. (3 studies; 3880 patients 2354 chewers, non-chewers 1526) Risk ratio = 6.853; 95% CI; 2.653-17.678
  • and continuous data
    • Pocket depth (4 studies, 958 patients, 754 chewers, 204 non-chewers) standard mean difference (SMD) = 0.398, (95%CI: 0.238-0.557)
    • Gingival recession  ( 2 studies, 407 patients, 325 chewers, 82 non-chewers)  SMD=0.317, (95%CI; 0.072- 0.563).
    • Attachment loss (4 studies, 958 patients, 754 chewers, 204 non-chewers) SMD= 0.664, (95% CI; 0.503-0.824).


The authors concluded: –

The results of this meta-analysis have shown that the khat chewing habit produces a destructive and adverse effect on periodontal, oral health.


Periodontal disease is one of a number of oral diseases that have been associated with its use although this and mucosal white lesions have been the most frequently reported (Al-Maweri et al).

This review has used a standard methodological approach and shown a positive relationship between khat chewing and damages to periodontal tissues. However, it should be noted that almost all the studies are cross-sectional in nature and show a marked heterogeneity as noted by the authors. The included studies cover a wide age range from 12-65yrs and the authors provide no details on whether any other confounders (eg. smoking, medical status) were taken into account. A majority of the studies involved males, although, women also chew khat but not to the same extent. Consequently, the findings should be viewed with caution.


Primary paper

 Al-Akhali MS, Al-Moraissi EA. Khat chewing habit produces a significant adverse effect on periodontal, oral health: A systematic review and meta-analysis. J Periodontal Res. 2017 Jun 18. doi: 10.1111/jre.12468. [Epubahead of print] Review. PubMed PMID: 28626895.

Other references

Al-Maweri SA, Warnakulasuriya S, Samran A. Khat (Catha edulis) and its oral health effects: An updated review. J Investig Clin Dent. 2017 Aug 19. doi: 10.1111/jicd.12288. [Epub ahead of print] Review. PubMed PMID: 28834423.

Picture credit

By Ferdinand Reus from Arnhem, Holland (I love my qat) CC BY-SA 2.0



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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. A former editor of the Evidence-Based Dentistry Journal and chief blogger for the Dental Elf website until December 2023. Derek has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Derek retired from the NHS in 2019 remaining as a part-time senior lecturer at Dundee Dental School until the end of 2023.

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