Cris 'Cyborg' Justino ﻿is usually the one drawing blood ... but the UFC star made an exception last week ... hitting up a Brazilian hospital to donate some of her own.

TMZ Sports has learned Cyborg visited Our Lady Of Grace Hospital in Curitiba (her hometown) ... and spent time hanging out with pediatric cancer patients and children with autism.

A spokesperson for the hospital says Justino "chatted and took pictures with our patients." She also "donated a pair of autographed gloves" ... and gave a pint of blood at the blood bank.

"The visit went great and our patients were really happy with the surprise."