Use the adjective caustic to describe any chemical that is able to burn living tissue or other substances, or, figuratively, a statement that has a similarly burning effect. Caustic in this sense means harshly critical.
In the chemical sense, a near synonym is corrosive. In the figurative sense, near synonyms are biting, scathing, and sarcastic. The source of the word caustic is Latin causticus, from Greek kaustikos, from kaiein "to burn."