Patrick Byrne, the CEO of Overstock.com, has announced that he is taking a leave of absence from his post at the e-commerce site because of complications from hepatitis C virus (HCV), CNN Money reports. As of now, it’s unclear when, or if, the American entrepreneur will return to the job.

Byrne believes he contracted a rare strain of hep C in Xinjiang, China, more than 30 years ago after a doctor there sewed up a head wound under “less-than-ideal conditions.” Byrne was diagnosed with Stage IV liver damage last summer and recently completed a course of HCV treatment. However, Byrne noted that “only time will tell” whether he has beaten the disease.

Byrne is no stranger to health issues. When he was 22 years old, he was diagnosed with testicular cancer and has had multiple recurrences and complications related to it ever since, including heart problems and more than 100 surgeries. His combined illnesses have significantly escalated over the last six months.

Mitch Edwards, former CEO of BitTorrent and SkullCandy and general counsel for Overstock.com for the last six months, will be taking over Byrne’s position in the interim. Byrne helped launch Overstock.com in 1999. The online shopping site made nearly $1.7 billion in sales last year.