The showbiz matriarch has been left angry by the show and its creators who used the 'Machete' star's plight as part of a storyline in the episode which aired in the US last night (17.11.10).
In the show, guest star Gwyneth Paltrow is seen playing substitute Spanish teacher Holly Holliday who instructs her students how to speak the language by asking them questions about the Hollywood actress - who is currently completing a court-ordered rehab programme.
In the scene, Holly asks pupils in Spanish, accompanied by English subtitles on screen: "Lindsay Lohan is totally crazy, right?"
She then asks: "How many times has Lindsay Lohan been to rehab?"
The final disparaging remark sees the teacher tell her class, "Please get into groups and discuss how many times Lindsay Lohan has been in rehab," when she needs to speak to a student in private.
Website Gossip Cop reports Dina as telling them "our lawyers are sending a letter" to 'Glee' on the grounds the show allegedly defamed the actress.
A representative for Lindsay added: "Lindsay has an issue that millions of people around the world are dealing with yet 'Glee' is treating addiction as a laughing matter."
The 24-year-old star is currently scheduled to remain at the Betty Ford Center until January 3 after failing two court-ordered drugs tests in September, testing positives for cocaine and amphetamines.