Acute and subacute psychoactive effects of Kambô, the secretion of the Amazonian Giant Maki Frog (Phyllomedusa bicolor): retrospective reports

Data were collected anonymously via paper-and-pencil questionnaires distributed at a drug-information event in Berlin and through Kambô practitioners. Participants returned completed questionnaires by pre-paid mail; all procedures received ethics approval from Charité Universitätsmedizin Berlin (EA2/185/17). The study comprised two parts: retrospective assessment of the acute subjective effects of a single exemplary Kambô session, and assessment of subacute effects only if that session had occurred within 2–3 weeks prior to completion. Demographics and lifetime drug-use histories were recorded. Validated psychometric instruments were used for acute effects: the Altered States of Consciousness (ASC) Rating Scale (both 5D-ASC and 11-ASC analyses), the Phenomenology of Consciousness Inventory (PCI), the Mystical Experience Questionnaire (MEQ30) and the Challenging Experience Questionnaire (CEQ). For subacute effects the Persisting Effects Questionnaire (PEQ, extended German version of 140 items) and an unpublished 23-item Connectedness Scale (CS) were administered; CS scores are presented by item due to lack of prior validation. As a data-quality criterion, records with an unreliable PCI response pattern (reliability index h > 2) were excluded. Analyses used standard scoring procedures for each instrument. The investigators performed one-sample t-tests against zero for the ASC, MEQ and CEQ scales (for comparability with previous datasets) and described PCI items on their bipolar 7‑point anchors. Data visualisation and summary statistics (means, SDs, boxplots) were produced with RStudio and ggplot2. The authors note that no quantitative assay of Kambô composition or standardised dosing per burn point was available, so dose–response assessment was not possible.

From 27 returned questionnaires, five were excluded for PCI reliability, leaving n = 22 for the acute-effects analyses. The subacute assessment was completed by 14 participants, with two excluded for incomplete PEQ/CS data, leaving n = 13 for subacute analyses. The sample reported extensive prior experience with psychoactive substances: 68.2% (15/22) had lifetime experience with serotonergic hallucinogens and 86.4% (19/22) with ritual plants or traditional indigenous medicines; cannabis lifetime use was 95.5% (21/22). Participants rated spiritual practices as relatively important (mean 72.7% ± 21.8%). Administration and immediate-session characteristics: Kambô was applied by an alternative health practitioner or neo-shaman in 68.2% (15/22) of cases, by an indigenous shaman in 9.1% (2/22) and by a layperson in 13.6% (3/22). Sessions were mostly individual (63.6%, 14/22) and commonly took place in a healing place or temple (52.4%, 11/21 where specified). The mean number of burning points was 7 ± 2. Reported acute duration was under 15 minutes for 27.3% (6/22), 30–59 minutes for 50.0% (11/22), and 60 minutes or longer for 13.6% (3/22). When asked if Kambô induces inebriation, 22.7% (5/22) answered yes. Acute subjective effects assessed by standardised scales were generally mild to moderate and did not resemble classical serotonergic psychedelic states. On the ASC rating scale, scores on dimensions typically elevated by psychedelics (for example Complex Imagery, Experience of Unity, Spiritual Experience, Insightfulness and Blissful State) were relatively low. MEQ30 factor means were likewise low, with a few higher outliers but not the high prevalence of full mystical-type experiences seen with high-dose serotonergic psychedelics. CEQ responses indicated that acute challenging aspects were dominated by physical distress rather than psychological crises: fear, paranoia, isolation and other psychologically centred "bad trip" symptoms were rarely endorsed. PCI results showed reductions in both positive and negative affect consistent with comparisons to hypnotic or meditative states; items for self-awareness, rationality, attention and memory suggested participants did not retrospectively feel confused or muddled. Subacute outcomes (n = 13) showed predominantly positive persisting effects. On the PEQ, 46% (6/13) rated their Kambô session as strongly spiritually significant, including two participants who placed it among the most spiritually significant experiences of their lives. Regarding personal meaningfulness, 54% (7/13) placed the experience among their ten most meaningful life experiences and four participants among the five most meaningful; one participant rated it the single most personally meaningful experience. Changes in well‑being or life satisfaction were reported as increased slightly by 62% (8/13) and as increased between 'moderate' and 'very much' by 38% (5/13). On the Connectedness Scale, high ratings were reported for internal aspects (for example connection to one's senses, emotions, body, deeper self and intuition), whereas connectedness to external domains (community, all humanity, spiritual essence or universal love) was less pronounced except for connectedness to nature.

Schmidt and colleagues interpret their findings as showing three principal patterns: first, acute Kambô effects reported retrospectively are predominantly somatic and produce only subtle alterations of consciousness that are qualitatively and quantitatively distinct from serotonergic psychedelic states. The ASC and MEQ data support this, with low scores on dimensions typically elevated by psychedelics and few full mystical-type experiences. The CEQ indicated that acute challenges were mostly physical rather than the psychologically driven crises sometimes observed with psychedelics. Second, the investigators observed notable positive subacute or persisting effects up to 2–3 weeks post-session. These included improved mood, increased well‑being, altruistic or positive behavioural changes and reports of personal and spiritual significance. The authors note overlaps with descriptions of psychedelic "afterglow" phenomena—in particular elevated mood and social/behavioural gains—but emphasise that the subacute profile after Kambô is not preceded by an acute psychedelic state and that intensity and qualitative features differ from the after-effects reported after high-dose LSD or psilocybin. Third, about half the respondents retrospectively appraised the experience as highly personally or spiritually meaningful. The investigators discuss plausible mechanisms without asserting causation: peptides in Kambô may act on the autonomic, endocrine, immune and peripheral systems, and ritual/expectation and symbolic cleansing narratives may contribute to psychological change. They acknowledge that most peptides are unlikely to cross the blood–brain barrier and that opioid peptides in the secretion have been reported to be centrally active only with intrathecal administration, so direct central pharmacological accounts are speculative. The authors also summarise safety concerns from case reports—psychosis, dermatomyositis, toxic hepatitis, sudden death, hyponatraemia and SIADH possibly related to excessive water intake—and stress that the observed pattern could reflect complex interactions between peripheral pharmacology, neuro‑endocrinological responses and non‑pharmacological factors. Key limitations are explicitly stated: the retrospective and anonymous design, recruitment via a workshop and practitioner networks that may bias toward positive expectations, the absence of a control or placebo condition, lack of standardised dosing or chemical quantification of Kambô preparations, and a small sample size. The investigators recommend randomised placebo‑controlled trials and further research to disentangle pharmacological from ritual and expectancy contributions to both acute and subacute effects.

The study concludes that retrospective reports of acute Kambô effects differ markedly from serotonergic psychedelic experiences: acute responses are dominated by intense physical reactions and inwardness rather than the perceptual and ego‑loosening features of psychedelics. Nevertheless, Kambô was associated with appreciable positive subacute effects—improved mood, increased wellbeing and reports of personal and spiritual significance—that resemble some elements of psychedelic "afterglow" phenomena, albeit without a preceding psychedelic state. The authors suggest that Kambô may produce transformative effects through a combination of peripheral physiological action and ritual/psychological mechanisms, and they call for controlled trials to clarify these processes and safety profiles.