Lindsay Lohan Had

Multiple Dirty Drug Tests

9/17/2010 9:05 PM PDT BY TMZ STAFF
Lindsay Lohan failed more than one drug test ... sources tell TMZ.

TMZ broke the story that Lindsay tested positive for cocaine last week.  Sources connected with the case tell us Lindsay failed another test as well -- we're told it was not for cocaine, but they would not be more specific.

And our sources say ... the tests were both conducted within a short span of each other.

Lindsay could face 30 days behind bars for each failed drug test.