The 20 year-old actress was "overheated and dehydrated," after spending more than 12 hours shooting in 105 F (40.5 C) heat, her representative, Leslie Sloane-Zelnick, told the celebrity news show "The Insider."
Lohan spent a couple of hours being treated, received a Vitamin B shot and was released from the hospital, Sloane-Zelnick said. The publicist could not immediately be reached by Reuters for further comment.
Lohan, who stars in director Robert Altman's current release "A Prairie Home Companion," was filming scenes for the upcoming "Georgia Rule," in which she portrays a rebellious teenager who is sent to live with her grandmother.
Sloane-Zelnick told "Insider" that Lohan is expected to be back at work on the set on Thursday.
Her sudden illness comes as the Los Angeles area swelters under a heat wave that has gripped California for the past several days, causing a number of deaths and pushing the state's power grid to the brink of failure.