Oil of clove is not always benign.

"In general, the use of cloves is regarded as safe for food use; however, when taken in large doses in its undiluted oil form or in clove cigarettes, side effects may occur. These include the following:

    * Vomiting
    * Sore Throat
    * Seizure
    * Sedation
    * Difficulty breathing
    * Hematemesis
    * Kidney Failure
    * Liver damage
    * Erectile dysfunction
    * Prolonged ejaculation
    * Seizure
    * Stomach irritation

Although the most common complaint of large doses of cloves is GI upset, those with kidney or liver disorders should avoid large doses of cloves. Serious side effects are more commonly reported in young children. There is insufficient evidence for cloves and its use in pregnancy or nursing."

http://altmed.creighton.edu/Cloves/Side%20effects.htm