The symptoms of oxalic acid poisoning include the following: 1. the symptoms of kidney damage, oxalic acid poisoning mainly refers to the calcium oxalate crystals in oxalic acid, which cause damage to the body, this damage is mainly manifested in the kidney, once too much calcium oxalate crystals are deposited in the kidney, it will seriously damage the kidney function, there will be hematuria, proteinuria, urinary difficulties, and in serious cases, it will lead to kidney failure. Oxalic acid poisoning can damage the kidneys and is treated by blood filtration to protect the kidneys. 2. Oxalic acid poisoning can cause gastrointestinal reactions, and as an acid, oxalic acid can stimulate and corrode the gastrointestinal tract, causing nausea, vomiting, diarrhea, abdominal pain and perforation. 3. lead to skin ulcers and other symptoms.