Apparently borax has been used in Chinese medicine for hundreds of years. Called "硼砂" in Chinese, it is used either alone or with other herbs to treat a variety of ailments, including cancer. The famous Chinese medical practitioner Li Shizhen recorded the characteristics and uses of borax in The Compendium of Materia Medica, a text written in the 16th century during the Ming Dynasty and was since translated into a number of languages.

Maybe understanding Chinese could prove difficult for some here, the following passage appeared in The Compendium:

“硼砂，气味甘，微咸，凉，暖，无毒。入肺、胃经。主治消痰止嗽，破瘕结喉痹。大明，上焦痰热，生津液，去口气，消障翳，除噎膈反胃，积块结瘀，阴疒贵骨哽，恶疮及口齿诸病。鼻血不止，硼砂50 g，水服立止。劳瘵有虫，硼砂、硇砂、兔屎等分为末，蜜丸梧子大，每服7丸，生甘草1份，新水1盅，揉汁送下”

As a partial translation, it claimed that borax could heal a number of ailments, including "reducing phelgm and stopping cough", "mouth and teeth diseases" and tumors. Interestingly, the dose it recommended for "nose bleeding" was 50g.