MD, PhD, FMedSci, FRSB, FRCP, FRCPEd

Wet cupping is a therapy traditionally used in several cultures. It involves superficial injuries to the skin and subsequently the application of a vacuum cup over the injured site. This procedure would draw a small amount of blood into the cup, and this visible effect was taken as a sign that the humors or life forces or whatever are being restored.

The treatment is obviously painful and carries the risk of infection. But does it work? There are not many clinical trials of this form of alternative medicine, and I was therefore thrilled to find a new paper with a randomised clinical trial.

The aim of this clinical trial was to evaluate the effectiveness and safety of wet cupping therapy as the sole treatment for persistent nonspecific low back pain (PNSLBP). The investigators recruited 80 with PNSLBP lasting at least 3 months and randomly allocated them to an intervention group (n=40) or to a control group (n=40). The experimental group had 6 wet cupping sessions within 2 weeks, each of which were done at two bladder meridian (BL) acupuncture points. The control group had no such treatments. Acetaminophen was allowed as a rescue treatment in both groups. The Numeric Rating Scale (NRS), McGill Present Pain Intensity (PPI), and Oswestry Disability Questionnaire (ODQ) were used as outcome measures. Numbers of acetaminophen tablets taken were compared at 4 weeks from baseline. Adverse events were recorded.

At the end of the intervention, statistically significant differences in all three outcome measures favouring the wet cupping group compared with the control group were seen. These improvements continued for another two weeks after the end of the intervention. Acetaminophen was used less in the wet cupping group, but this difference was not statistically significant. No adverse events were reported.

The authors concluded that wet cupping is potentially effective in reducing pain and improving disability associated with PNSLBP at least for 2 weeks after the end of the wet cupping period. Placebo-controlled trials are needed.

Every now and then – well, actually in alternative medicine this is not so rare an event – I come across a study that ‘smells to high heaven’. This one certainly does; to be precise, it has the stench of TOO GOOD TO BE TRUE.

Apart from the numerous weaknesses of the study design, there is the fact that the results are do simply not seem plausible. Low back pain has a natural history that is well-studied. We therefore know that the majority of cases do get better fairly quickly regardless of whether we treat them or not. In this study, the control group did not improve at all, as shown on the impressive graph below (the grey line depicts the symptoms in the control group and the black one those of the cupping group).

To me, the improvement of the experimental group looks much like one might expect from the natural history of back pain. If this were true, the effect of wet cupping would by close to zero and the conclusion drawn by the authors of this trial would be false-positive.

But why was there no improvement in the control group?

I do not know the answer to this question. All I know is that it is this unexplained phenomenon which has created the impression of effectiveness of wet cupping.

6 Responses to Wet cupping: too good to be true?

  • As far as I get, nonspecific means they just could not find the cause or did not look enough. Maybe they should have focused on such things as lifestyle, body weight …
    Then there were too few patients, especially for multicentre study – I mean, they very likely looked for patients at some clinics and doctor treating patient with chronical disease affects patient in other ways too, including how much patient is going to tell any doctor. The there is individual perception of what is pain and what is improvement ….
    If you have large number of patients from many physicians, it somehow levels out, but if there are few patients from few physicians you can unconsciously put those that are very demanding and always complaining into one group and those that are grateful for even the slightest improvement (slightly more attention for physician, slightly less pain) – into another.

  • There is one good statement in that “Placebo-controlled trials are needed.” Wet cupping is a classic highly dramatic placebo and we know dramatic placebos give better results, especially on surveyed patient perceived outcomes.
    The control patients did not receive standard of care treatment – not even exercises or normal amounts of analgesics.
    This makes me amazed that only 5% of patients dropped out, and they did due to travel.

  • Wet cupping seems to be quite common in the islamic world. Try a search for “Hijama” on Youtube and you will find a flood of bloody cupping quackery.
    Below is a gross example from Turkey. I do not understand what the blokes are saying but I hear them repeating “İnşallah” all the time, which means “God willing”. They certainly need help from holy spirits if this is going to help with anything more than possibly Hemochromatosis* or polycythemia, which are about the only genuine indications for blood-letting.

    THis must be at least a couple of pints of blood. No wonder the brother on the left seems rather stunned.
    Nonsense prevails 🙂
    https://www.youtube.com/watch?v=_zLZGLezMIM

    • At least the health care person is wearing gloves. It would be interesting, however, to culture his tie.

    • That looks like real blood loss. And, judging from my experience, things become less important then. Although people get used to – my record is 3,3 g/dl hemoglobin which was discovered accidentally, although when I got in the hospital the first time, result was 10 g/dl and I could not cross room without help.
      I wonder, where the history of cupping (how many times, how often is taken into account into these studies?). Actually do constant anaemia make person more pain tolerant or less pain tolerant?

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