A preliminary toxicological comparison of two structurally related compounds and a health risk assessment of a specific exposure


A global tobacco company.


The use of 3,4-dihydrocoumarin (DHC) in a cigar head paste formulation had been challenged based on its structural similarity to coumarin, banned for food additive use in several countries. Bibra was asked to compare the toxicological profiles of these compounds and, subsequently, to conduct a health risk assessment of a specific exposure to DHC in the head paste. Both oral and inhalation exposure scenarios were considered possible.

Project goals

To summarise and compare the key aspects of the toxicological profiles of coumarin and DHC, including Expert Group assessments and/or health criteria values (HCVs) where appropriate. To provide an independent opinion on whether a specific repeated (oral and inhalation) exposure to DHC, as a constituent of a head paste formulation, would pose any significant risks to the health of the consumer.


Due to the short timeline available, the focus of the hazard assessment was on data from Expert Group reviews. The data were presented in a tabular format to facilitate direct comparison between the compounds for each of the endpoints and a lay summary was generated to highlight the key differences between the two compounds. The comprehensive dataset for DHC was utilised to calculate independent HCVs for the ensuing health risk assessment.

Project outcome

Bibra concluded that, in terms of general systemic toxicity, DHC is less toxic than coumarin by the oral route. The HCVs derived by bibra for DHC were roughly one order of magnitude greater than the analogous values identified for coumarin. Overall, the data indicate that repeated long-term exposure at the calculated oral and inhaled dose levels would pose no significant risks of systemic or local toxicity to the consumer.

Project Team

Daniel Threlfall

Pete Watts


Consumer products

More recent work Info about us Meet our team