Canola Oil is not toxic to humans although some people may be allergic to the Canola Oil and cannot use it to cook with.
If the Canola Oil makes you sick then it's likely that you're just allergic to the Canola Oil and or stomach just doesn't like it.
Canola oil is a much healthier cooking oil than regular vegetable oil is and can reduce your risk of developing heart disease and can help with your Cholesterol levels.