Is Thuja occidentalis Harmful?

I recently purchased drops for tension and headache therapy which contains Thuja occidentalis. I thought there was information that thuja was harmful. Please provide some feedback.

Thuja occidentalis contains a strong volatile oil, thujone, which is the main constituent of the herb that provides medicinal benefits. Thujone is stimulating to the nervous system and to the bronchial, urinary and uterine muscles, irritating and toxic in large doses. Because of its toxicity, thuja should be taken internally only under medical supervision. It should be taken in very small doses for short periods of time.
Because of its stimulating actions, thuja should be avoided in dry, irritable coughs and in pregnancy. Because of its toxicity, it should be avoided in breast feeding.
The product that you purchased may be homeopathic. Homeopathic doses are hundreds of times weaker than normal herbal doses, and so may not have the aggravating effects mentioned above.