Yes. In 2020 the International Agency for Research on Cancer (IARC) of the World Health Organization classified opium use, whether smoked or eaten, as "carcinogenic to humans" (Group 1), the same group as tobacco smoking [1]. In the Golestan study of 50,000 Iranians, opium use raised the risk of cancer by 40%, and the risk of lung, bladder and laryngeal cancer was more than doubled [2]. Opium does not protect the heart: deaths from heart and blood vessel disease were higher in users [3].
Key points
- Opium is a definite carcinogen (IARC Group 1) [1].
- The more and the longer, the higher the risk: a dose–response link was seen for cancers of the oesophagus, stomach, lung, bladder and larynx [2].
- Opium is not a medicine for the heart, diabetes or blood pressure: users had more deaths from heart and blood vessel disease [3].
One important step: give up opium and get help
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Do not use it on your own for pain or illness
Even low but long-term use was linked to higher mortality, including in people who had no major illness before starting opium [3]. For pain, take a prescribed medicine at a known dose (cancer pain).
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Do not stop suddenly; make a plan with a doctor
Someone who has used it for a long time gets withdrawal symptoms if they stop suddenly. A family doctor or addiction treatment centre can support safe withdrawal with medicines.
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Tell your doctor
Mention any opium use, even if you have stopped; knowing it, your doctor will pay closer attention to warning signs of oesophageal, stomach, lung and bladder cancer [2].
| Cancer | Increased risk in opium users |
|---|---|
| All cancers | 40% higher [2] |
| Oesophagus | 38% higher [2] |
| Stomach | 36% higher [2] |
| Lung | More than twice [2] |
| Bladder | Nearly three times [2] |
| Larynx | More than twice [2] |
The link was the same in smokers and non-smokers, men and women. Eating opium (rather than smoking it) was also linked to brain and liver cancer [2].
When should I contact a doctor?
If you use or have used opium and have any of these symptoms, see a doctor soon: difficulty or pain swallowing, unexplained weight loss, a long-lasting cough or bloody sputum, blood in the urine, or hoarseness for more than a few weeks. See the signs in symptoms of oesophageal cancer (Persian) and symptoms of lung cancer (Persian).
Frequently asked questions
People say opium is good for the heart and diabetes. Is that true?
No. In the Golestan study, opium use was linked to an 86% increase in death from all causes and an 81% increase in death from heart and blood vessel disease [3].
I only use a little, occasionally.
Notes for doctors (for physicians)
For physicians
IARC classification (Monograph 126). Opium consumption (smoked or ingested) is Group 1, with sufficient evidence for cancers of the larynx, lung and bladder and limited evidence for the oesophagus, stomach, pancreas and pharynx [1].
Golestan cohort. 50,045 people aged 40 to 75, median follow-up 10 years; use was validated with urinary metabolites. HR for all cancers 1.40 (1.24 to 1.58), with a dose–response relationship [2]. Mortality: all-cause HR 1.86 (1.68 to 2.06), cardiovascular 1.81, cancer 1.61; the strongest associations were with asthma, tuberculosis and COPD [3].
In practice. Ask about opium use in the history, treat it as a risk factor like smoking, and refer for cessation.
Scientific evidence
Related cancer types
Related questions
References
3 referencesShow all references, 2 with a study cardClose the reference list
Numbers in the text, such as [1], refer to these sources. Sources with a “Study card” button are summarised in the site’s evidence library.
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This page is based on reputable scientific sources and was last updated on 27 October 2026. The content of this website is for educational and informational purposes only and does not replace consultation, diagnosis or treatment by a specialist physician. Consult your treating physician about any treatment decision.
