'Diamonds Are Forever' Girl Plenty O'Toole 911 Call -- 'She's Having Trouble Breathing'

You know you're in trouble when the urgent care facility you go to for help has to call 911 ... which is exactly what happened with "Diamonds Are Forever" star Lana Wood this week ... TMZ has learned.

As TMZ previously reported, Wood -- who played Plenty O'Toole in the classic James Bond flick -- suffered a terrible allergic reaction at her Fillmore, CA home and went to the local urgent care.

When the urgent care couldn't fix the problem, they dialed 911 and told the dispatcher one of their patients was having trouble breathing.

It all worked out in the end ... Wood is now feeling much better. Doctors believe the allergic reaction was triggered by an ingredient in her Frosted Mini-Wheats.