With respect I unaware of any muscle relaxant qualities of Oxalic Acid. I am not saying that they do not exist I just an unaware of them. It is however quite toxic and can lead to kidney failure associated with the formation of calcium oxylate crystals (this is one of the causes of antifreeze toxicity). It is also highly tissue irritating especially to the respiratory and GI tract. Just FYI since the topic was brought up. James