Lancashire's game against Essex was halted for over half an hour after an air ambulance landed on the Old Trafford pitch to attend to an ill spectator.
The helicopter landed next to the old pavilion while Essex's Simon Harmer was facing a delivery from Lancashire's Graham Onions early on the third day.
It is believed that the spectator left the ground in one of three ambulances that also attended the scene.
Lancashire Cricket Club tweeted: "Play halted due to a medical emergency, with one of the spectators taken ill.
"The air ambulance has landed on the outfield. Let’s hope they (sic) going to be okay."
Play resumed at 11.45pm.
The two sides took lunch with Lancashire 6-2 in their second innings, a lead of five runs.