Reasons and frequencies of hydrofluoric acid burns have been investigated during our work in the toxicological information centre (1987/88) and by means of the patients treated in the last five years in our ICU: Almost all of the cases are due to accidental hurts (29/30). About 3/4 of the accidents (22/30) happened during occupational exposure. One third of the patients (10/30) have been exposed to hydrofluoric acid fume and 18/30 suffered from percutaneous burns especially of the distal parts of the upper limbs. Oral intoxications are rare (2/30). The observed quotes of the information centre are equivalent to those of our own patients (eight cases from 1984 to 1989). Hydrofluoric acid burns are treated with calcium. Concerning the frequent burns of the limbs, the intra-arterial therapy proved good and prevailed during the last years over the classical infiltration therapy. Only early treatment avoids necroses. Unfortunately the particularity of this percutaneous intoxication is often misunderstood.