The 68-year-old actor, who is starring as flamboyant entertainer Liberace in latest movie "Behind The Candelabra", said the cancer was not a result of hard drinking and heavy smoking, and was instead caused by a sexually transmitted disease.
"Without wanting to get too specific, this particular cancer is caused by HPV (human papillomavirus), which actually comes about from cunnilingus," he explained.
"I did worry if the stress caused by my son's incarceration didn't help trigger it. But yeah, it's a sexually transmitted disease that causes cancer."
"And if you have it, cunnilingus is also the best cure for it," he added.
His son Cameron is serving a 10-year prison sentence for drug possession and dealing.
The two-time Oscar winner revealed in 2010 that he was battling with stage-four cancer, but beat the disease thanks to a gruelling programme of chemotherapy and radiotherapy.
"I have to check in regularly -- now it's every six months -- but I'm more than two years clear," he said. "And with this kind of cancer, 95 percent of the time it doesn't come back."
Research studies from Malmo University's Faculty of Odontology and in The New England Journal of Medicine both suggest a correlation between oral sex and throat cancer.
HPV infection is also the cause of 99 percent of cases of cervical cancer, according to studies cited by Britain's National Health Service (NHS).
Douglas' wife, Oscar-winner Catherine Zeta-Jones, in April received further treatment for bipolar disorder.
The Welsh actress, 43, won an Academy Award in 2003 for her supporting role in "Chicago" and has appeared in films such as "Traffic" and "Ocean's Twelve."