Two pregnant women were taken to hospital after being found crammed in a container at a port with dozens of other suspected illegal immigrants.
Seven people were taken to Colchester General Hospital and 61 others assessed by the East of England Ambulance Service, which was called about the container at Harwich International Portat around 10pm yesterday.
An ambulance spokesman said: "The patients who were taken to hospital were suffering from abdominal and chest pains and were feeling faint.
"None are in a life-threatening or serious condition.
"The remaining 61 were released to the UK Border Agency officials."
The spokesman said a range of different nationalities was involved, both men and women, including two who were pregnant, and who were among those taken to hospital.
The container involved is thought to have come from Holland.