In the future, incense might need to carry a health warning, just like tobacco. That's the conclusion of researchers who for the first time have compared the effects of burning incense indoors to inhaling tobacco smoke.

Previous research has already shown how incense smoke can be harmful to a person's health, but these new findings suggest that it's worse than cigarettes by several measurements – a result that may alarm some in Asian countries, where incense burning is a common practice in the home and a traditional ritual in many temples.

"Clearly, there needs to be greater awareness and management of the health risks associated with burning incense in indoor environments," said Rong Zhou of the South China University of Technology, in a statement to the press.

The researchers tested two types of incense against cigarette smoke to see their effects on bacteria and the ovary cells of Chinese hamsters. Both the incense products contained the common ingredients agarwood and sandalwood, which are used in incense for their fragrances.

The findings, published in Environmental Chemistry Letters, showed that incense smoke is mutagenic, which means it can cause mutations to genetic material, primarily DNA. Compared to the cigarette smoke, the incense products were found to be more cytotoxic (toxic to cells) and genotoxic (toxic to DNA). Of the 64 compounds identified in the incense smoke, two were singled out as highly toxic.

Obviously none of this sounds very good, and for people frequently exposed to incense smoke in indoor environments, hopefully it serves as a wake-up call: mutagenics, genotoxins, and cytotoxins are all linked to the development of cancers.

It's worth pointing out that the research comes with a number of caveats. The researchers only worked with a small sample size, and so far their testing hasn't directly involved humans.

Perhaps more importantly, the research was conducted with the assistance of a Chinese tobacco company. This kind of corporate involvement in scientific studies inevitably leads to all sorts of raised eyebrows within academic research circles – especially when Big Tobacco is one of the players. However, in this case there doesn't seem to be anything overtly pro-tobacco in the paper, other than the demonstration that something else may be even more toxic than cigarettes!

Further, the researchers point out in their conclusion that the chemical composition of smoke produced by two such very different products doesn't actually bear a direct comparison for consumer use, as we don't inhale incense and cigarette smoke in the same way.

"[W]e cannot simply conclude that incense smoke is more toxic than cigarette smoke because of differences in consumption styles of these products," they write.

The researchers hopes their findings will lead to the development of a system to regulate the sale of incense products and introduce measures to reduce smoke exposure.