The 27-year-old actor had a mini-stroke last year, reported E! Online.
"Almost a year to the day, I experienced another mini stroke. Hopefully that will be the last. Miserable," Muniz tweeted.
Last November, the actor had described his stroke to a show as, "I couldn't say words, and I thought I was saying them. And my fiancee was looking at me like I was speaking a foreign language."
After wrapping 'Malcolm in the Middle', Muniz launched a career as a musician.