Risk assessment of coumarin using the bench mark dose (BMD) approach: Children in Norway which regularly eat oatmeal porridge with cinnamon may exceed the TDI for coumarin with several folds - Fotland TO, Paulsen JE, Sanner T, Alexander J, Husøy T; Norwegian Scientific Committee for Food Safety
Intake estimates of coumarin show that small children eating oatmeal porridge several times a week sprinkled with cinnamon could have a coumarin intake of 1.63mg/kgbw/day and may be exceeding the TDI several fold. Adults drinking cinnamon-based tea and consuming cinnamon supplements also can exceed TDI. The coumarin intake could exceed the TDI by 7- to 20-fold in some intake scenarios. Such large daily exceedances of TDI, even for a limited time period of 1-2weeks, cause concern of adverse health effects.

Toxicology and risk assessment of coumarin: focus on human data - Abraham K, Wöhrlin F, Lindtner O, Heinemeyer G, Lampen A; Federal Institute for Risk Assessment (BfR), Berlin, Germany.
Coumarin is a secondary phytochemical with hepatotoxic and carcinogenic properties. For the carcinogenic effect, a genotoxic mechanism was considered possible, but was discounted by the European Food Safety Authority in 2004 based on new evidence.
This allowed the derivation of a tolerable daily intake (TDI) for the first time, and a value of 0.1 mg/kg body weight was arrived at based on animal hepatotoxicity data.
However, clinical data on hepatotoxicity from patients treated with coumarin as a medicinal drug is also available. This data revealed a subgroup of the human population being more susceptible for the hepatotoxic effect than the animal species investigated.
The cause of the high susceptibility is currently unknown; possible mechanisms are discussed. Using the human data, a TDI of 0.1 mg/kg body weight was derived, confirming that of the European Food Safety Authority.
Nutritional exposure may be considerable, and is mainly due to use of cassia cinnamon, which is a popular spice especially, used for cookies and sweet dishes. To estimate exposure to coumarin during the Christmas season in Germany, a telephone survey was performed with more than 1000 randomly selected persons.
Heavy consumers of cassia cinnamon may reach a daily coumarin intake corresponding to the TDI.

Herbal Concotion - Salvia officinalis (Common Sage), Cloves, Thyme, Oregano, Garlic, Marjoram, Dill, Cinnamon & Chives - by Jtrismegistus [EROWID]

Today I embarked on a shamanic experiment with a combination of household herbs which included sage, garlic, chives, marjoram, thyme, oregano, dill weed, and cinnamon;