Three of the passengers hail from Ramanathapuram while one is from Sivaganga.
They had arrived last night by Malindo airlines.
They did not disclose any gold at the counter, but hand metal detector used by the customs officials at the airport gave them away.
When questioned, the four admitted to have swallowed gold pellets in the form of buttons, customs sources said.
The four are being fed with green leafy vegetables to ensure speedy exit of the contraband.