By Analou de Vera A health official said that the Food and Drug Administration (FDA) is now conducting an investigation after four tricycle drivers have died after drinking an alleged contaminated coconut wine, also known as “lambanog.” (MANILA BULLETIN) Health Undersecretary Rolando Enrique Domingo said that the FDA was already checking if the coconut liquor that was consumed by the victims was registered with the agency, and if was, indeed, contaminated with a poisonous ingredient. "FDA is now investigating to check if the product is registered and if the seller has a license to operate. They are also trying to secure samples for testing," said Domingo in a text message sent to The Manila Bulletin. The health official also encouraged the public to only purchase products registered with the FDA. "We advise the public to refrain from buying and consuming unregistered products," he said. Four tricycle drivers in Novaliches, Quezon City were earlier reported to have died after they drank “lambanog” in a drinking spree. Thirteen others, meanwhile, were reportedly hospitalized. The fatalities were identified as Delfin Bangayon, Dennis Cuadra, 37; Alvin Reyes, 42; and Crispulo Mateo Jr., 43. Investigation showed that the fatalities experienced severe stomach pain. Meanwhile, police is also conducting an investigation if there was a foul play involved in the incident.