Astanga Hrudaya
असमग्राभिघाताच्च सोऽपि वैकल्यमश्नुते । तस्मात् क्षारविषाग्न्यादीन् यत्नान्मर्मसु वर्जयेत् ॥ ६९ ॥
even then they cause distortions (irregularity) hence the use of ksara (application of caustic alkali) visa (poisonous drugs), agni (cautery by fire) etc. on the vital spots should avoided as far as possible (with all efforts).
english translation
asamagrAbhighAtAcca so'pi vaikalyamaznute । tasmAt kSAraviSAgnyAdIn yatnAnmarmasu varjayet ॥ 69 ॥
hk transliteration by Sanscript