Background: Hydrofluoric acid_(HF) is widely used in many industrial and domestic settings such as etching glass, and polishing metals. HF is one of the most corrosive inorganic acids and can produce progressive and serious tissue necrosis with severe pain. Since HF chemical burns can be asymptomatic for the first few hours, it is crucial to understand its toxicity and the early use of antidote. Case: A 37-year-old man presented with erythematous lesion and pain on his face, anterior neck, both forearms, both thighs, and left ankle after injury resulting from a chemical burn caused by HF. He showed normal vital signs and dyspnea, but complained of a sore throat. Liquid form of HF had splashed on his face and anterior neck first and run down his forearms and thighs while working at HF supply tanks. Some of the HF was splashed into his mouth. He immediately removed his clothes and showered with abundant water. A 4.5% calcium gluconate jel was applied to the involved area. He was given subcutaneous injection of 10% calcium gluconate solution. During 17 days of admission he didn’t show any signs of systemic intoxication or deep tissue defects. Conclusions: Immediate cleansing of the affected area with running cold water is the first critical treatment for a chemical burn due to HF. Applying calcium gluconate gel within one hour was very effective for preventing further damage to the injured area as well as systemic injury. In order to reduce the risk of accident and perform first-aid treatment quickly, it is imperative to provide workers with safety education and establish safety facilities.