"I'm feeling like a very large turd on a very thin stick," Brando wrote in 1991.
"I'm holed up in bed and taking everything from sled dog urine to powdered East Indian vulva," stated the letter, giving the impression that Brando was sick, the New York Daily News reported.
"I'm sure it will be a kick in the ass, and I hate to miss it -- Happiest of birthdays to you, Charlie," it ended.
The handwritten letter was signed "Love, Marlon" and has a reserve of $1,000 on the auction house Web site, Lelands.com.
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