Rhubarb stalks may lend a super tart tang to strawberry pie; but their leaves offer something altogether different. Rhubarb leaves contain oxalic acid, a chemical compound found in bleach, metal cleaners and anti-rust products. The leaves also contain anthraquinone glycosides. Eating the leaves can lead to a burning sensation in the mouth and throat, nausea and vomiting, gastric pain, shock, convulsions and even death.
Although rhubarb sold at the store genrally has most of the leaves removed, be careful if you grow it at home; although using every part of a vegetable is generally great ... in this case, the shock, convulsions and death aren't quite worth it.