If by "toxic" you mean that eating peanuts can cause death, then the answer is emphatically yes. Check this:

http://www.associatedcontent.com/article/425790/peanut_allergies_are_you_nuts_you_better.html?cat=5

Or just Google "Fatalities due to Peanuts".

No evidence of MSG fatalities unless consumed in exceedingly large doses. But, if a person is subject to migraine and MSG is a trigger, an MSG migraine can make you wish for death.