Lindsay Lohan and Samantha Ronson have been spotted kissing and holding hands -- but has the rehabbed Hollywood starlet needed to lean on her DJ gal pal for more than just a fun time?

Last night, the inseparable two were spotted at an emergency room in an apparent health scare -- reports say Sam brought Lindsay in -- and they stayed for two hours.

The cause for the visit to the Century City hospital is unknown. Lindsay is known to suffer from acute asthma, and has a tattoo to remind her to "breathe."