ANTIOCH -- Authorities are investigating how a margarita was inadvertently served to a toddler early this week at a local Applebee's restaurant, causing the boy to become sick.

Police say a 2-year-old Antioch boy drank an unspecified amount of the tequila-based drink -- instead of the ordered apple juice -- after it was served to him in a covered, plastic sippy cup at the Applebee's on Hillcrest Avenue.

The toddler was doing fine Thursday after being rushed to the hospital Monday night when he grew drowsy and started vomiting a few hours after ingesting the alcoholic beverage, his mother, Kim Mayorga, said.

"I wasn't going to make a big deal about it," she said Thursday, "but then he got sick."

The serving appeared to have been accidental, Antioch police Lt. Pat Welch said.

Applebee's Vice President Randy Tei said no other children reported ingesting the mixed drink.

"It was completely an accident," Tei said. "Once we found out about it, we reacted as swiftly as possible to put corrective procedures in place so it doesn't happen again."

Mayorga said she was dining with her three children and her father Monday night at the restaurant when she noticed her 2-year-old son, Julian, acting strangely. She had ordered his favorite drink -- apple juice -- but he kept making funny faces and pushing away his plastic, lidded cup.

"Finally, I'm like, 'That's crazy. He loves apple juice,'" she said.

Concerned, Mayorga opened the lid and checked the juice.

She was instantly hit by the reek of booze.

"When I called the waitress over, I couldn't believe what I was saying: 'You served my son alcohol.'"

Corporate representatives later told Mayorga that the mistaken beverage poured in her son's cup was their "top-shelf" margarita, complete with Triple Sec and high-quality tequila.

The restaurant keeps apple juice and the premade "top-shelf" liquor fusion in two identical-looking plastic bottles on ice behind the bar, Tei said.

Markings on the bottles differentiate the two, but a manager who was working at the time mistakenly grabbed the margarita mixture instead of the apple juice jug. The children's cup is opaque white with graphics around the sides and a cover, making it difficult to see in, Tei said.

There are no plans to discipline the manager or server, he added.

"We absolutely believe it was an honest mistake," Tei said. "And those workers have learned a very important lesson by it."

The company will reimburse the Mayorgas for their medical bills. It will also no longer keep the juice in the similar-looking container, Tei said.

Mayorga says the company has been very apologetic and offered free meals at the family restaurant, but she added, "If they think I'm going back there, they're ridiculous."

Police said the case will be forwarded to the Alcohol Beverage Control board and the Contra Costa District Attorney's Office, but they don't anticipate that charges will be filed, Welch said.

Cassandra Braun covers East County crime and safety. Reach her at 925-779-7174 or cbraun@cctimes.com.