The evidence does not say cannabis cures colds or the flu. The more honest read is that cannabinoids interact with immune and inflammatory pathways that overlap with why viral illnesses feel so miserable: cytokines, airway inflammation, congestion, pain, sleep disruption, and systemic inflammation.
Cannabis Use and Systemic Inflammation — CARDIA Study
Year Published: 2019
Possible Indication: Systemic inflammation; cytokine response; biomarker signal
Key Takeaway: Human observational study looking at inflammatory markers including CRP, fibrinogen, and IL-6. Some markers appeared lower in cannabis users, but the association weakened after adjustment. Useful evidence of a possible signal, not proof.
Possible Indication: Systemic inflammation; cytokine response; mixed/negative biomarker signal
Key Takeaway: Another human biomarker study found cannabis use was not clearly associated with lower hs-CRP, IL-6, or fibrinogen. This is an important counterweight to the more bullish inflammation narrative.
Cannabinoids and Inflammatory Cytokines — Systematic Review
Year Published: 2021
Possible Indication: Cytokine response; inflammation; immune modulation
Key Takeaway: Broad review of in vivo studies found cannabinoids, especially CBD, CBG, and CBD+THC, often reduced inflammatory cytokines. This is one of the best citations for the cytokine-modulation thesis, although much of the evidence is preclinical rather than human clinical.
CBD-Rich Cannabis Fraction and Lung Inflammation Markers
Year Published: 2021
Possible Indication: Respiratory inflammation; cytokine response; cold/flu research rationale
Key Takeaway: In lung-cell models, a CBD-rich cannabis extract reduced inflammatory markers including IL-6 and IL-8. Relevant to respiratory inflammation, but still cell-line/preclinical evidence, not proof that cannabis treats colds or flu.
CBD and Mild/Moderate COVID-19 — Randomized, Double-Blind Placebo-Controlled Trial
Year Published: 2022
Possible Indication: Viral illness; antiviral; cytokine response; negative/neutral efficacy signal
Key Takeaway: One of the more direct viral-illness tests. CBD 300 mg/day added to standard care did not show convincing clinical benefit in COVID progression. Important negative/neutral clinical evidence.
Cannabis Use and Sinonasal Symptoms — U.S. Adult Study
Year Published: 2022
Possible Indication: Cold symptoms; nasal congestion; sinus symptoms
Key Takeaway: Regular cannabis users reported lower odds of sinonasal symptoms, including congestion-type symptoms. Interesting for the congestion thesis, but observational and not causal.
CBD and Inflammatory Markers in Advanced Cancer — Randomized Trial
Year Published: 2023
Possible Indication: Systemic inflammation; cancer-related inflammation; safety
Key Takeaway: Trial measured inflammatory markers such as CRP in advanced cancer patients. It did not establish a clean broad anti-inflammatory clinical benefit. Useful because it shows that human biomarker evidence remains mixed.
Possible Indication: Antiviral; viral entry/replication; immune modulation
Key Takeaway: Summarizes antiviral signals from hemp cannabinoids, including possible effects on viral entry, replication, and immune response. Interesting, but still mostly preclinical and hypothesis-generating.
Possible Indication: Flu; respiratory safety; smoked-route risk
Key Takeaway: Important cautionary study. Cannabis smoke exposure disrupted host defense and increased viral burden in influenza-infected mice. This cuts against smoked cannabis as a sensible route during respiratory viral illness.
Possible Indication: Sinus symptoms; congestion; chronic rhinosinusitis
Key Takeaway: Retrospective observational study suggesting a possible relationship between cannabis use and lower chronic rhinosinusitis risk. Interesting sinonasal signal, but not proof that cannabis treats congestion or colds.
Possible Indication: Safety; liver risk; high-dose CBD
Key Takeaway: Randomized trial in healthy adults found that daily CBD at clinically meaningful doses caused liver enzyme elevations in some participants. Important safety caveat, especially for high-dose CBD or drug interactions.
CBD/THC and Inflammatory Biomarkers — Systematic Review / Meta-Analysis
Year Published: 2025
Possible Indication: Systemic inflammation; cytokine response; biomarker evidence
Key Takeaway: Human evidence across inflammatory biomarkers remains mixed. Cleanest summary: cannabinoid anti-inflammatory biology is real, but human clinical evidence is not yet definitive.
Excellent! Would very much be interested in your findings/protocol. Cheers, J
Pls check the chat! https://scottrgrossman.substack.com/publish/chat
What the Research Actually Says
The evidence does not say cannabis cures colds or the flu. The more honest read is that cannabinoids interact with immune and inflammatory pathways that overlap with why viral illnesses feel so miserable: cytokines, airway inflammation, congestion, pain, sleep disruption, and systemic inflammation.
Cannabis Use and Systemic Inflammation — CARDIA Study
Year Published: 2019
Possible Indication: Systemic inflammation; cytokine response; biomarker signal
Key Takeaway: Human observational study looking at inflammatory markers including CRP, fibrinogen, and IL-6. Some markers appeared lower in cannabis users, but the association weakened after adjustment. Useful evidence of a possible signal, not proof.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC6883146/
Cannabis Use and Inflammatory Biomarkers
Year Published: 2020
Possible Indication: Systemic inflammation; cytokine response; mixed/negative biomarker signal
Key Takeaway: Another human biomarker study found cannabis use was not clearly associated with lower hs-CRP, IL-6, or fibrinogen. This is an important counterweight to the more bullish inflammation narrative.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC7894624/
Cannabinoids and Inflammatory Cytokines — Systematic Review
Year Published: 2021
Possible Indication: Cytokine response; inflammation; immune modulation
Key Takeaway: Broad review of in vivo studies found cannabinoids, especially CBD, CBG, and CBD+THC, often reduced inflammatory cytokines. This is one of the best citations for the cytokine-modulation thesis, although much of the evidence is preclinical rather than human clinical.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC8266561/
CBD-Rich Cannabis Fraction and Lung Inflammation Markers
Year Published: 2021
Possible Indication: Respiratory inflammation; cytokine response; cold/flu research rationale
Key Takeaway: In lung-cell models, a CBD-rich cannabis extract reduced inflammatory markers including IL-6 and IL-8. Relevant to respiratory inflammation, but still cell-line/preclinical evidence, not proof that cannabis treats colds or flu.
Link: https://www.nature.com/articles/s41598-021-81049-2
CBD and Mild/Moderate COVID-19 — Randomized, Double-Blind Placebo-Controlled Trial
Year Published: 2022
Possible Indication: Viral illness; antiviral; cytokine response; negative/neutral efficacy signal
Key Takeaway: One of the more direct viral-illness tests. CBD 300 mg/day added to standard care did not show convincing clinical benefit in COVID progression. Important negative/neutral clinical evidence.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC9587798/
Cannabis Use and Sinonasal Symptoms — U.S. Adult Study
Year Published: 2022
Possible Indication: Cold symptoms; nasal congestion; sinus symptoms
Key Takeaway: Regular cannabis users reported lower odds of sinonasal symptoms, including congestion-type symptoms. Interesting for the congestion thesis, but observational and not causal.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC9335247/
CBD and Inflammatory Markers in Advanced Cancer — Randomized Trial
Year Published: 2023
Possible Indication: Systemic inflammation; cancer-related inflammation; safety
Key Takeaway: Trial measured inflammatory markers such as CRP in advanced cancer patients. It did not establish a clean broad anti-inflammatory clinical benefit. Useful because it shows that human biomarker evidence remains mixed.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC10576726/
Antiviral Activity of Hemp Cannabinoids — Review
Year Published: 2023
Possible Indication: Antiviral; viral entry/replication; immune modulation
Key Takeaway: Summarizes antiviral signals from hemp cannabinoids, including possible effects on viral entry, replication, and immune response. Interesting, but still mostly preclinical and hypothesis-generating.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC10133872/
Cannabis Smoke and Influenza A in Mice
Year Published: 2023
Possible Indication: Flu; respiratory safety; smoked-route risk
Key Takeaway: Important cautionary study. Cannabis smoke exposure disrupted host defense and increased viral burden in influenza-infected mice. This cuts against smoked cannabis as a sensible route during respiratory viral illness.
Link: https://pubmed.ncbi.nlm.nih.gov/38020563/
Cannabis Use and Chronic Rhinosinusitis Risk
Year Published: 2025
Possible Indication: Sinus symptoms; congestion; chronic rhinosinusitis
Key Takeaway: Retrospective observational study suggesting a possible relationship between cannabis use and lower chronic rhinosinusitis risk. Interesting sinonasal signal, but not proof that cannabis treats congestion or colds.
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12658615/
FDA-Linked CBD Safety Trial — Liver Enzyme Elevations
Year Published: 2025
Possible Indication: Safety; liver risk; high-dose CBD
Key Takeaway: Randomized trial in healthy adults found that daily CBD at clinically meaningful doses caused liver enzyme elevations in some participants. Important safety caveat, especially for high-dose CBD or drug interactions.
Link: https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2836267
CBD/THC and Inflammatory Biomarkers — Systematic Review / Meta-Analysis
Year Published: 2025
Possible Indication: Systemic inflammation; cytokine response; biomarker evidence
Key Takeaway: Human evidence across inflammatory biomarkers remains mixed. Cleanest summary: cannabinoid anti-inflammatory biology is real, but human clinical evidence is not yet definitive.
Link: https://www.mdpi.com/1422-0067/26/23/11618