Tara Reid Explains Why She Feels She Was Drugged at Chicago Hotel Bar

Tara Reid is explaining why she's convinced someone slipped something into her drink that knocked her out ... and she says she's fortunate she wasn't raped.

The "American Pie" star joined us on "TMZ Live" Monday and took us through her harrowing night in Chicago ... she says her drink was spiked at a hotel bar.

We have video of Tara in a wheelchair in the hotel lobby and on a stretcher on her way to the hospital ... she says folks at the hospital told her she was "drugged."

Thing is, Tara says the explanation she got at the hospital was all very "vague" ... telling us she didn't bother to ask what kind of drug laid her out for several hours.

Tara says she went down to the bar around 10:30 PM Saturday and was in the hospital around midnight, and woke up 8 hours later ... but in the videos we have of her at the hotel, she's slouched in a wheelchair around 12:30 AM Sunday and is on a stretcher being loaded into an ambulance just before 1 AM.

She estimated her drink was allegedly spiked about 30 minutes after she got to the bar ... telling us she left the glass at the bar to go outside for a smoke. When she came back, she says there was a napkin covering her glass -- she says she didn't put it there -- and she removed the napkin and drank her wine.

Tara's had well-documented substance abuse issues in the past ... but she insists she only had one glass of wine at the hotel before she woke up in a hospital bed.

Worth noting ... folks who were there tell us in their limited interaction with Tara at the hotel bar, she seemed fine, but things went downhill fast -- and her behavior changed rapidly after the bar closed up and folks took the party out into the lobby.

Tara mentions there were a bunch of YouTubers in the hotel filming when she was there ... and she says she's considering filing a police report to get to the bottom of what happened.