CHS occurs in chronic cannabis users and is characterised by cyclical nausea, vomiting and abdominal pain with symptoms alleviated by hot bathing. Extensive emergency department evaluations are often unrevealing. Our patient’s heavy use (2 g/day for 7 years) and hot-shower relief support CHS; his recurrent vomiting produced hypokalaemic metabolic alkalosis and prerenal azotaemia. CHS is frequently missed at first, prompting repeated ED visits and normal investigations, and is classically refractory to standard antiemetics and IV fluids.^2,3

As CHS often fails to respond to first-line antiemetics, clinicians have turned to alternative treatments. Benzodiazepines, benzamides, and atypical antipsychotics (such as haloperidol) have been reported to help in refractory CHS, but such agents carry notable risks.^3,5 CHS is often refractory to standard treatment, and while haloperidol can relieve symptoms, even a single dose may cause serious adverse effects (dystonia, NMS). ⁵ In contrast, topical capsaicin has emerged as a promising option. Numerous case reports in adults (and more recently in adolescents) describe rapid symptom relief following abdominal capsaicin cream when usual antiemetics failed.^2,5 These successes underscore that our patient’s response was consistent with emerging experience: after capsaicin application his intense retching and pain abated within minutes and he tolerated oral intake by 90 minutes.

The efficacy of capsaicin in CHS is hypothesized to stem from its action on the transient receptor potential vanilloid-1 (TRPV1) channel. TRPV1 is a heat-sensitive nociceptor expressed on peripheral sensory neurons that also modulates emesis pathways.^2,4 Capsaicin, a potent TRPV1 agonist, triggers a rapid influx of cations (Ca²+ and Na+) and release of neuropeptides (such as substance P and CGRP) from these nerves. ⁴ This accounts for the acute burning sensation we noted after application. Crucially, sustained activation leads to a refractory state: prolonged TRPV1 opening causes desensitization (known as “defunctionalization”) of the nerve endings, depleting substance P and other peptides. ⁶ In effect, the capsaicin induces a temporary disconnect of the aberrantly sensitized pain/emetic fibers. This has been described as a novel desensitization analgesia where TRPV1 hyperactivation by capsaicin yields downstream analgesic and antiemetic effects. ⁴ Capsaicin mimics the effect of the patient’s hot-water bathing – activating TRPV1 on cutaneous afferents – but drives it further, producing longer-lasting receptor inactivation. Indeed, CHS patients universally report hot showers as palliative (likely through TRPV1),^2,4 and topical capsaicin appears to recapitulate that benefit in a more potent way. Some experts have suggested that chronic cannabis may itself dysregulate TRPV1 signaling (perhaps via CB1-mediated hypofunction), so that CHS represents a state of TRPV1 downregulation that can only be reset by a super-agonist like capsaicin.^4,7

While mechanistically appealing, the evidence base for capsaicin in CHS is still limited. Reports of cannabinoid hyperemesis syndrome treated with topical capsaicin are limited. ⁴ Available case series suggest potential benefit but lack a controlled study design. For instance, Wagner and colleagues described 43 CHS patient visits treated with capsaicin and found reduced symptom scores, but no change in ED length of stay – partly due to study limitations.^3,4 The first randomized data come from a small pilot trial (Dean et al., 2020) in which 0.1% capsaicin cream applied to the abdomen significantly lowered nausea scores at 60 minutes compared to placebo. In that study, about 30% of the capsaicin group had complete resolution of nausea by 60 minutes (versus none in placebo). ⁸ Thus, the literature – though not yet robust – consistently shows rapid symptomatic improvement with capsaicin in otherwise refractory CHS.^2,8

Topical capsaicin has a favorable safety and convenience profile. It is inexpensive, available over-the-counter in various strengths (we used 0.1% cream), and its side effects are limited to local discomfort. The classic side effect is a burning or stinging sensation at the application site.^2,8 Our patient reported intense warmth for about 15–30 minutes, but tolerated it well. Unlike systemic antiemetics or sedatives, capsaicin has no significant central or cardiac effects. ³ This low side-effect burden and ease of use make it attractive as an adjunct in CHS management. In contrast, alternative therapies (including haloperidol, benzodiazepines and antipsychotics) carry risks of sedation, extrapyramidal reactions, or other systemic toxicity, making capsaicin a safer option when first-line treatments have failed. ⁵

We performed a structured literature search of PubMed, EMBASE, and Google Scholar to identify published case reports and case series describing the use of topical capsaicin in patients with CHS. Eligible studies were peer-reviewed human reports of any age group in which CHS—defined as chronic daily cannabis use with cyclic vomiting and/or abdominal pain relieved by hot bathing—was treated with topical capsaicin for symptom control. Reviews, editorials, conference abstracts, and studies lacking original patient-level data were excluded, as were publications involving non-topical routes of capsaicin administration. No language or date restrictions were applied. Reference lists of included articles were hand-searched to identify additional relevant reports. The search strategy used combinations of the terms “cannabinoid hyperemesis syndrome,” “CHS,” “cannabis hyperemesis,” and “capsaicin,” using Boolean operators as appropriate. Final inclusion was limited to peer-reviewed articles reporting individual cases or case series. Across the peer-reviewed literature, 18 patients with cannabinoid hyperemesis syndrome treated with topical capsaicin have been reported. These patients were reported across six publications (3 case reports and 2 case series).^2,5,9-11 (Table 3).

Study (Year)	Patients (age/Sex)	Cannabis use & CHS history	Capsaicin regimen	Outcome (time to relief)
Graham et al (Pediatrics 2017) 5	2 adolescents (16–17 y, both)	Daily heavy cannabis (≥2 yrs)	0.025% cream applied periumbilically (1 mm thick)	Both had cessation of vomiting and pain within ∼30 min
Dezieck et al (Clin Tox 2017) 9	13 patients (8M/5F; 20–40 y)	Daily cannabis (years)	Topical capsaicin cream (concentration NR; abdominal)	All 13 reported symptom relief (time not specified)
Moon et al (ACG Case Rep J 2018) 10	23 y male	Daily marijuana (≥5 yrs)	0.075% cream, 15×25 cm abdomen, reapplied q4h	Abdominal pain & nausea improved after 1st dose; nausea gone after 2nd dose; pain resolved after total of 4 doses
Aziz et al (Case Rep Gastrointest Med 2020) 2	41 y female	Daily cannabis (periods of excess use)	0.1% cream, applied over epigastrium and abdomen, TID	Dramatic pain/vomiting relief within 24 h (near-complete resolution)
Huang et al (Pain Med Case Rep 2025) 11	34 y pregnant female (11 wk)	Chronic cannabis use	Capsaicin cream (strength NR) applied abdominally	Significant improvement in nausea/pain shortly after application
Current Case (2025)	28 y male	Daily cannabis (∼7 yrs, ∼2 g/day)	0.1% cream, ∼2 g over entire abdomen (single application)	Retching ceased in ∼10 min; pain ↓ to 2/10 by 30 min; pain 0/10 by 90 min

All reported CHS cases involved long-term heavy cannabis use (typically daily use for years) and featured the classic hot-shower–relief phenomenon. In each case, standard antiemetics and IV fluids had failed to abort symptoms, prompting use of topical capsaicin. Symptom response was rapid in nearly all reports.^2,5,9-11 For example, a 41-year-old female with refractory CHS experienced near-complete symptom resolution within 24 hours of thrice-daily 0.1% abdominal capsaicin cream. ² Similarly, a young adult male had marked improvement in pain and vomiting a few hours after two doses of 0.075% cream. ¹⁰ In Dezieck et al.’s series of 13 adult CHS patients, all 13 reported relief after capsaicin application. ⁹ In the only pediatric series, two adolescent CHS patients (ages ∼16–17) whose symptoms were resistant to conventional therapy responded fully to 0.025% capsaicin cream. ⁵ Across studies, capsaicin concentrations ranged from 0.025% up to 0.1%. Higher-strength formulations (0.1%) were often associated with dramatic, rapid relief, ² whereas even 0.025% cream was effective in adolescents. ⁵ Patients commonly reported an intense burning sensation initially (lasting ∼15–30 minutes), but this was well-tolerated. No serious adverse effects were reported. In a large retrospective review (57 patients), capsaicin use yielded a median pain score drop from 8/10 to 5.5/10, and 42% required no further therapy afterwards; importantly no systemic side effects were observed. ¹² Reported CHS cases varied in age, sex, and context, including pediatric, adult, and pregnancy-related presentations. Capsaicin concentrations and dosing regimens differed, but outcomes were consistently positive. Rare treatment failures were associated with low or infrequent dosing, whereas higher concentrations (0.1%) reliably produced effective relief. Overall, topical capsaicin rapidly suppresses symptoms in refractory CHS across diverse populations.^2,5,9-11