The 46-year-old star of Fox's "The Bernie Mac Show" says he has sarcoidosis, which causes inflammation of the body's tissues, most frequently in the lungs, E! Online reports.
"No one knows where sarcoidosis comes from or where it starts, and there's no known cause for this condition that effects primarily minorities," said Mac. He was diagnosed with the disease in 1983.
The actor's condition landed him in the hospital last summer after finishing work on "Ocean's Twelve" and Fox delayed filming of his show's fourth season.
Sarcoidosis, fatal in 5 percent of the cases, was cited as the cause of death for football great Reggie White last December. Basketball legend Bill Russell also suffers from the disease.
Mac publicist Matt Labov says it's a "treatable illness and not deadly."