The research rests on the findings that first of all the sheer act of stopping to smell may help, "..smelling causes the brain to interrupt all of its conscious activities for a split second and to reorganize all disordered activity," and second, that smelling an enjoyable scent will trigger the production of Dopamine, the chemical responsible for the production of a good disposition.
However, an article which investigated the topic came up with conflicting reports. The parents seem to be happy with the results but the experts say it's not the best solution.
"From an attachment perspective, it's a critical role for the parent to help children learn how to calm down, and the parent is really essential in that, not a bottle of oil,"abc4.com: Investigating Tantrum 911
Here's a video showing the effects of Tantrum 911,