Agave is a placebo. So use it for cough.

Agave is a placebo.  So use it for cough.

Here is the rule:

If a medicine is no better than placebo, the medicine is ineffective.

If a surgery is no better than sham surgery, the surgery is ineffective.

If an pseudo-medicine is no better than placebo, the pseudo-medicine is effective. It's the placebo effect.


I have written about the use of honey for cough at Science-Based Medicine. Short summary: it does not work and the studies that purport efficacy are deeply flawed.


But honey is still touted as a treatment for cough and you do not want to give honey to children because of the risk of botulism. So hows about agave nectar ? So in an interesting study, Placebo Effect in the Treatment of Acute Cough in Infants and Toddlers they compared agave nectar, placebo and no intervention in children with cough.

Unfortunately they did not use an objective endpoint like recording the cough and seeing if they made a real impact. No, they used a survey of the patients both before and after the intervention looking at

Cough frequency, cough severity, cough bothersomeness, congestion severity, rhinorrhea severity, and cough effect on child and parent sleep.

It is akin to the (I think) classic NEJM article on asthma and placebo that confirmed that placebo has no effect on objective endpoints but does improve subjective endpoints and that having an medical intervention, even a placebo intervention, has salubrious effects on patients perceptions of their disease.

What is interesting about this study is that since is done on young children it is more like veterinary medicine, since the children can't provide the information directly.

As expected, agave and placebo had more effect than doing nothing:

Significant differences in symptom improvement were detected between the study groups (P < .05 for all, except P = .06 for cough bothersomeness), with agave nectar and placebo proving to be superior to no treatment, but no significant differences for any outcome were found when comparing agave nectar against placebo.

So, in the classic interpretation, agave, being no better than placebo, does nothing. However, instead it is suggested to try agave

Based on the findings, he added, pediatricians can think about advising parents to try agave nectar for children with cough. "It's something they can consider, as an alternative to telling parents to do nothing." The treatment "appears harmless," Dr. Paul said, and may make both parents and babies feel better.

And all the coverage suggests giving agave or placebo a try, it will make the cough better.

And they suggest that using a placebo is just fine:

"If a placebo is of low cost, has no or minimal adverse effects, and the parent or patient is not deceived about the nature of the treatment," they write, "it seems largely irrelevant whether or not the benefit from a clinical encounter is because of a clinician's recommendation for the use of an evidence­ based treatment or from a placebo effect."

The tricky part is in the phrase " the parent or patient is not deceived", which I wonder how you could accomplish.

"Agave is no better than placebo which means it has no effect at all on the cough. Give it a try."

I suspect that will not go over well.

The real placebo effect was probably on the parents, not the children, who were relieved that their coughing child was getting treatment.

The study that should have been done: agave, placebo, and no treatment in the children with or without Ativan for the parents. I suspect the most improvement would be in those who received the Ativan.

Points of Interest 11/04/2014
Points of Interest 11/03/2014