I just finished reading the biography "Heavier than Heaven," which relied on interviews with Cobain's relatives. It says several doctors had diagnosed him with IBS after numerous scope tests over the years. It didn't tell whether he was a D or C type--only listed the complaints of pain and "burning nausea." However, in 1990 he wrote an (unreleased) song titled "Imodium." The man never ate vegetables, preferring instead a diet of pizza, tacos, Kentucky Fried Chicken and the like. He claimed that his prodigious heroin use was an attempt to quell the pain from his digestive problems. In one interview, he said, "After living with constant pain for five years, you just want to kill yourself." Sadly, he finally did.