Over 25 people were admitted to various hospitals in Ernakulam district on Tuesday after having food at an eatery in North Paravoor.
According to the police, 27 people with symptoms of food poisoning have been hospitalised and their condition is said to be stable.
A case has been registered against the owner of the restaurant and an investigation is on.
"The number of affected persons may go up," a police official told PTI.
Local authorities have shut the restaurant following the incident, which comes days after the state government launched a campaign against restaurants and eateries selling contaminated food.
Recently, a nurse working at the Kottayam medical college died after consuming a dish from the eatery there.